Predominant Tree Species Research Articles

Depletion of atmospheric gaseous elemental mercury by plant uptake at Mt. Changbai, Northeast China

Abstract. There exists observational evidence that gaseous elemental mercury (GEM) can be readily removed from the atmosphere via chemical oxidation followed by deposition in the polar and sub-polar regions, free troposphere, lower stratosphere, and marine boundary layer under specific environmental conditions. Here we report GEM depletions in a temperate mixed forest at Mt. Changbai, Northeast China. The strong depletions occurred predominantly at night during the leaf-growing season and in the absence of gaseous oxidized mercury (GOM) enrichment (GOM < 3 pg m−3). Vertical gradients of decreasing GEM concentrations from layers above to under forest canopy suggest in situ loss of GEM to forest canopy at Mt. Changbai. Foliar GEM flux measurements showed that the foliage of two predominant tree species is a net sink of GEM at night, with a mean flux of −1.8 ± 0.3 ng m2 h−1 over Fraxinus mandshurica (deciduous tree species) and −0.1 ± 0.2 ng m2 h−1 over Pinus Koraiensis (evergreen tree species). Daily integrated GEM δ202Hg, Δ199Hg, and Δ200Hg at Mt. Changbai during 8–18 July 2013 ranged from −0.34 to 0.91 ‰, from −0.11 to −0.04 ‰ and from −0.06 to 0.01 ‰, respectively. A large positive shift in GEM δ202Hg occurred during the strong GEM depletion events, whereas Δ199Hg and Δ200Hg remained essentially unchanged. The observational findings and box model results show that uptake of GEM by forest canopy plays a predominant role in the GEM depletion at Mt. Changbai forest. Such depletion events of GEM are likely to be a widespread phenomenon, suggesting that the forest ecosystem represents one of the largest sinks ( ∼ 1930 Mg) of atmospheric Hg on a global scale.

Species composition and diversity of non-forest woody vegetation along roads in the agricultural landscape

Abstract Non-forest woody vegetation represents an important component of green infrastructure in the agricultural landscape, where natural and semi-natural forest cover has only a low land use proportion. This paper focuses on linear woody vegetation structures along roads in the agricultural landscape and analyses them in three study areas in the Nitra Region, Slovakia. We evaluate species composition and diversity, species occurrence frequency or spatial distribution, their structure according to relatively achievable age and origin. For the evaluation of occurrence frequency, a Frequency Factor was proposed and applied. This factor allows a better comparison of different study areas and results in more representative findings. The study areas were divided into sectors based on visual landscape features, which are easily identifiable in the field, such as intersections and curves in roads, and intersections of roads with other features, such as cadastral or land boundaries, watercourses, etc. Based on the species abundance, woody plants present within the sectors were categorised into 1) predominant, 2) complementary and 3) mixed-in species; and with regard to their origin into 1) autochthonous and 2) allochthonous. Further, trees were categorised into 1) long-lived, 2) medium-lived and 3) short-lived tree species. The main finding is that among trees, mainly allochthonous species dominated. Robinia pseudoacacia L. was the predominant tree species in all three study areas. It was up to 4 times more frequent than other predominant tree species. Introduced tree species prevailed also among complementary and mixed-in species. Among shrubs, mainly native species dominated, while non-native species had a significantly lower proportion and spatial distribution. Based on these findings, several measures have been proposed to improve the overall ecological stability, the proportion and spatial distribution of native woody plant species. The recommendations and measures aim at enhancement of native species biodiversity, landscape identity and character, in order to meet the main landscape and biodiversity challenges identified in key biodiversity and landscape policies of Europe.

Stump sprouting of 19 upland hardwood species 1 year following initiation of a shelterwood with reserves silvicultural system in the southern Appalachian Mountains, USA

Models that quantify the probability of stump sprouting P(s) and sprout characteristics for predominant tree species in the southern Appalachian Mountains, USA are lacking. In this study, 375 plots (0.01 ha) were installed across five stands in eastern Tennessee and western North Carolina. Trees ≥3.8 cm diameter at 1.37 m above groundline (dbh) were tagged, and dbh and species recorded. Stands were regenerated using a two-aged silvicultural system (residual basal area (BA) <6.3 m2 ha−1). One growing season post-harvest, we recorded (1) sprouting (yes/no), (2) the number of sprouts per stump (sprout density), and (3) dominant (tallest) sprout height. Sprout density, sprout height, and P(s) were modeled as function of dbh, site index (SI), and BA. For white (Quercus alba L.), black (Quercus velutina Lam.), scarlet (Quercus coccinea Muenchh.), and northern red (Quercus rubra L.) oaks, and sweet birch (Betula lenta L.), yellow buckeye (Aesculus flava Aiton), and red maple (Acer rubrum L.), P(s) was inversely related to dbh. Sprout density was positively related to (1) dbh for red maple, yellow buckeye, sourwood (Oxydendrum arboreum L. (DC)), silverbell (Halesia tetraptera Ellis), and white basswood (Tilia heterophylla Vent.), and (2) SI for scarlet oak. For eight species, sprout height was influenced by dbh, SI, dbh and SI, or dbh and BA. Because stump sprouts are a primary source of regeneration, the information on stump sprouting produced for these 19 species can be used to quantify and predict early stand dynamics following regeneration harvests in these diverse southern Appalachian hardwood stands.

Analysis of Vegetation Structure Causing Top-Dying In Mangrove Forest Trees in the Sundarbans in Bangladesh

Sundarbans is the largest, biologically richest, and most extensive mangrove forest in the world (Christensen, 1984; Seidensticker and Hai, 1983; Hussain and Karim, 1994). Heritiera fomes (Sundri) is the predominant tree species, supporting about 65% of the total merchantable timber (Chaffey et al., 1985, and Siddiqi, 2001). A unknown and serious-killer disease (top dying) of H. fomes in Sundarbans is affecting millions of the trees. An inventory by Chaffey et al., (1985) revealed that there were about 45.2 million top dying trees in the Sundarbans of which 20 million had more than 50% of their crown affected by top dying. The loss of H. fomes will have a major impact on the Sundarbans mangrove ecosystem, which leads to economic losses. The vegetation structure was assessed in terms of tree height, bole diameter, species present, and regeneration status; and the intensity of top-dying within the plots was recorded on a rank scale. Most of the elements studied had no significant correlation with the top dying of Heritiera fomes. Of the hypotheses previously put forward to explain top-dying, the present results do not support enhanced salinity as the cause. It is likely that several of the above-mentioned environmental factors interact with each other to induce top dying in Sundri. However, the present results have showed that Sn, Exchangeable K, soil pH, Pb , Zn and Ni could be directly linked with top-dying of Heritiera fomes (Sundri) in Sundarbans, probably particularly by weakening the vigour of the trees and allowing other factors such as pathological agents to attack the plants.

Analysis of Water Parameters Causing Top-Dying in Mangrove Forest Trees in the Sundarbans in Bangladesh

Sundarbans is the largest, biologically richest, and most extensive mangrove forest in the world and representing 2.5 percent of the world’s natural mangrove forest (Saha, 1991), the Sundarban natural mangrove forest is still the largest natural single tract of mangrove forest and habitats in the world (Christensen, 1984; Seidensticker and Hai, 1983; Hussain and Karim, 1994) with 10, 029 km2 area. The total area of the part of Sundarban in Bangladesh is now about 6,017 km2 (Imam, 1982; Christensen, 1984; Chaffey et al., 1985), which arose due to the eastward shift of the Ganges (Blasco, 1977; Naskar 1999; and Bakshi, 1954; Thom, 1982). Heritiera fomes (Sundri) is the predominant tree species, supporting about 65% of the total merchantable timber (Chaffey et al., 1985, and Siddiqi, 2001). A unknown and serious-killer disease (top dying) of H. fomes in Sundarbans is affecting millions of the trees. An inventory by Chaffey et al., (1985) revealed that there were about 45.2 million top dying trees in the Sundarbans of which 20 million had more than 50% of their crown affected by top dying. The loss of H. fomes will have a major impact on the Sundarbans mangrove ecosystem, which leads to economic losses. Despite various hypotheses as to the causes of this top-dying, the underlying causes are still not well understood. The present work has explored some of the possible factors involved, focussing particularly on the relationship between the amount of top-dying in different places and the concentrations of a number of chemical elements present in the water, in order to test the hypothesis that chemical pollution might be responsible. Other factors such as the pH, salinity and nutrient status were also assessed. Nine plots were selected for sampling of water, and vegetation in order to categorise different areas in terms of their intensity of top-dying. 63 soil samples and 9 water samples were tested, mainly by ICPMS, to investigate certain parameters of the soil and water, such as Sn, Exchangeable K, Soil pH, Pb, Zn, Ni, soil pH, CEC, soil nutrients, soil moisture content, and elemental concentrations of 32 other elements. Most of the elements studied had no significant correlation with the top dying of Heritiera fomes. However, the present results have showed that some possible parameters in water in Sundarbans such as Salinity of water, water pH, Water EC, water nutrients could not be directly linked with top-dying of Heritiera fomes (Sundri) in Sundarbans.

Plant diversity in tropical deciduous forests of Eastern Ghats, India: A landscape level assessment

A landscape level plant diversity and population inventory was made in northern portion of eastern Ghat region of India comprising mostly dry deciduous and moist deciduous forests. A total of 444 transects of 0.5 ha (5 × 1000 m) area each was used for enumerating trees. Diversity and density of herbs, shrubs, lianas and regeneration of tree species were assessed from 5 x 5 m size plots within transects. A total of 882 species belonging to 532 genera and 129 families were recorded comprising of 263 tree species, 78 species of shrubs, 138 species of climbers/twinners and 403 species of herbs. Shorea robusta, Lannea coromandelica, Madhuca india and Diospyros melanoxylon were the predominant tree species where members of Euphorbiaceae, Rubiaceae, Fabaceae and Combretaceae contributed to maximum species richness, stand density and basal area. The stand density ranged from 268 to 655 stems ha−1 while basal area varied from 6.65 to 22. 28 m2 ha−1. The tree density and species richness decreased with increasing girth class; highest number of species and maximum density was recorded for 30 to 60 cm girth class. Shannon-Weiner Index and Simpson Index varied in the range of 1.85-2.05 and 0.013-0.018, respectively. Regeneration of many tree species was observed to be poor. Key words: Plant diversity, population structure, Eastern Ghat, India.

Molecular characterization of sawtooth oak (Quercus acutissima) germplasm based on randomly amplified polymorphic DNA

Sawtooth oak (Quercus acutissima) is a predominant tree species in the deciduous broad-leaved forest in China. It distributes in a large landscape area and can disperse in various ecology types. Molecular study on sawtooth oak can provide valuable information about the genetic diversity level and genetic relatedness on this important tree species. Insight into the genetic structure also provides resources of a species with its current feature and future evolutionary potential. The genetic structure of sawtooth oak was investigated by randomly amplified polymorphic DNA (RAPD). Twelve RAPD markers were used to assess genetic diversity of 408 individuals from 17 provenances enveloping most of the current distribution area of sawtooth oak. A total of 66 amplification products were detected, of which 49 bands (74.24 %) were polymorphic. Nei’s gene diversity, 0.2409, indicated a relatively high level of genetic variation in sawtooth oak germplasm. Analysis of molecular variance showed that most of the genetic diversity (87 %) was allocated within provenances. A combination of UPGMA dendrogram and STRUCTURE analysis was employed to estimate the genetic relationships of sawtooth oak germplasm; interestingly, the two methods presented similar grouping pattern with few discrepancies. Results revealed that 16 out of 17 provenances were clustered into one group, while the other 1 (LQ provenance) constituted a separate cluster. The data presented in this study suggested that the RAPD method was a valuable tool for estimation of genetic diversity and genetic relatedness of sawtooth oak germplasm. The present study also gave useful implications for germplasm conservation and new cultivar development for this promising energy tree species.

Trees and forests: a colour guide

The popularity of trees and forests as subjects for books is apparent from the number of such books to be found in the natural history sections of libraries and bookshops. Publications range in type from coffee-table books illustrated with magnificent photographs of trees, to the scientific, which deal with the biology of trees and the utilisation of timber. This book announces on its cover that it deals with biology, pathology, propagation, silviculture, surgery, biomes, ecology and conservation. It falls somewhere between the two extremes, being accessible to the general reader, while summarising some serious scientific issues. The editor, Brian Bowes, has assembled 14 chapters using a total of 16 authors selected for their expertise in the topics covered. After an introductory chapter (Brian Bowes) summarising the types of trees, their architecture, evolution and their importance for civilisation, there is a section of four chapters dealing with the world distribution of forests: northern boreal and montane (Aljos Farjon), temperate deciduous and rain forests (Hugh Angus), temperate mixed evergreen forests (Stephen D. Hopper, Erika Pignatti Wikus, Sandro Pignatti) and tropical and sub-tropical rain and dry forests (Ghillean T. Prance). Each chapter describes the environment in each zone and describes briefly its predominant tree species. This section is followed by a chapter on tree morphology, anatomy and histology, which gives an elementary account of secondary thickening in woody stems (Brian Bowes). This is a good basic account, but general readers may find parts of this difficult as it assumes a knowledge of the cell types found in wood. The fourth section deals with tree pathology, with the first chapter in this section describing the role of cell wall polymers in disease resistance in woody plants (Christopher T. Brett). This presents a good introduction to basic cell wall structure and considers the wall and its components in an original way. This is followed by a chapter on microbial and viral pathogens and plant parasites of plantation and forest trees in which Stephen Woodward describes the different major diseases that affect trees, their economic importance and management. A chapter by Clair Ozanne on insect pests complements the chapter by Woodward and completes this section. The final section of the book consists of five chapters that cover aspects of general and practical forestry, beginning with forest ecology (Peter A. Thomas), silvicultural systems (Peter Savill and Nick Brown), tree pruning and surgery (David Thorman), tree propagation (Brent McCown and Thomas Beuchel) and forest and woodland conservation (Ghillean T. Prance). Inevitably given the limited space available coupled with the fact that at least half of each page is occupied by photographs, the resulting chapters can best be described as tasters that will stimulate the reader to seek out more specialised works. In this they will be aided by a reading list for each chapter provided at the end of the book. Each topic is presented clearly and the book is well-written, very readable, and accessible to the general reader. However, as is also inevitable in attempting to condense as much as possible into very limited space, generalisations have been made here and there that the specialist reader may find over-simplified and with which they may disagree. As would be expected from the book's sub-title, it is what is usually described as lavishly illustrated. The photographs are in fact so numerous that it seems to have been necessary to keep them small, typically about 8 × 5 cm. In general the quality of the photographs is very good, but a number of those showing views of woodland or forest really should have been printed at a greater magnification to make their distinctive features clearer. For example, in the photograph of New Zealand's temperate mixed evergreen forest, the nikau palms it is claimed it shows are simply not distinguishable from the surrounding nondescript green mass of foliage. This is, however, a minor criticism of a book that will be very useful for students of economic botany in particular and as an introduction to forestry, arboriculture and conservation.

Landscape-level tree diversity assessment in tropical forests of southern Eastern Ghats, India

This large-scale, landscape-level study aims to assess tree species diversity, stem density and stand structure of six major tropical hill forests of southern Eastern Ghats, India, namely, Bodamalai (BM), Chitteri (CH), Kalrayan (KA), Kolli hills (KO), Pachaimalai (PM) and Shervarayan hills (SH). The Eastern Ghats of India is relatively under-studied compared with the Western Ghats biodiversity hotspot. The entire stretch of southern Eastern Ghats was divided into smaller grids of 6.25 km × 6.25 km, totaling to 120 grids. Within each grid, a belt transect of 0.5 ha (5 m × 1000 m) area was laid and all trees ≥30 cm girth at breast height (gbh) were enumerated. A total of 272 tree species (≥30 cm gbh) that belonged to 181 genera and 62 families were recorded in the total 60 ha area inventoried. Diversity indices such as Shannon, Simpson and Fisher's alpha indices were 2.44, 0.03 and 42.1, respectively, for the whole 60 ha area. One way ANOVA revealed that the species richness varied significantly across the six sites ( F (5,823) = 4.854, p < 0.0002). Also, the contribution of tree species to total species richness classified by three plant types viz. evergreen, brevi-deciduous and deciduous species varied significantly across the sites (One way ANOVA: F (2,15) = 10.05, p < 0.002). Similarity indices such as Jaccard and Sørensen showed that sites CH and KA are more similar in terms of species composition. The total stand density and basal area for the total 60 ha area were 27,412 stems (457 stems ha −1) and 1012.12 m 2 (16.9 m 2 ha −1), respectively. The stand density and basal area for the six sites ranged from 290 (in site BM) to 527 stems ha −1 (in site KA) and from 5.6 (in site BM) to 24.4 m 2 ha −1 (in site KO), respectively. Stand density and basal area of tree species varied significantly across the six hill complexes ( F (5,823) = 4.85, p < 0.0002 and F (5,823) = 2.71, p < 0.02, respectively). A positive correlation was obtained between stand density and species richness in sites PM ( r s = 0.65, p < 0.05) and SH ( r s = 0.67, p < 0.05), but not in other sites. The predominant tree species in the tropical forests of southern Eastern Ghats include Albizia amara, Euphorbia antiquorum, Canthium dicoccum var. dicoccum, Memecylon edule, Chloroxylon swietenia and Nothopegia heyneana. Taxonomically, Euphorbiaceae constituted the most diverse family with 25 species. Whereas, by tree abundance the Mimosaceae with 4126 stems enumerated from the 60 ha area formed the dominant family. Bray–Curtis cluster analysis, based on tree species composition and abundance revealed that the low-diverse site BM formed a separate entity from other hill complexes. This large-scale tree diversity inventory provides a baseline data for a variety of investigations and is expected to be useful for effective forest management and biodiversity conservation of southern Eastern Ghats region.

Indirect effects of timber extraction on plant recruitment and diversity via reductions in abundance of frugivorous spider monkeys

Abstract:The ecological effects of logging in the tropics have been analysed largely in terms of its impacts on species diversity and abundance. However, information is very limited regarding the impact of logging on ecological processes such as species interactions. Here we hypothesize that timber extraction per se, that is, in the absence of hunting, affects the abundance of the frugivorous spider monkey, Ateles geoffroyi, and that this has indirect effects on the recruitment of a predominant tree species, Manilkara zapota, and the diversity of the understorey plant community. We compared logged and unlogged sites, using a paired design. In each management condition we conducted line transects and interviews to evaluate spider monkey abundance and game preferences, respectively. Impact on plant recruitment and understorey diversity were evaluated using 2 × 2-m plots (N = 320) established under 40 M. zapota tree crowns. No spider monkeys were recorded in logged sites whereas they were abundant (15 ± 8 individuals per man-km) in unlogged sites. Interviews showed that spider monkeys are not hunted by local inhabitants. Logging was correlated with a reduction of the number of M. zapota fruits used by A. geoffroyi; an increase in the number of sites dominated by M. zapota; and a reduction in understorey plant diversity. Our results suggest that the absence of A. geoffroyi in logged sites can indirectly impact plant recruitment and diversity via the disruption of plant–frugivore interactions. Further work is needed to assess if these effects persist over the long term, to define if logging operations affect the overall diversity of tropical forests.

Post-fire natural regeneration of young stands on clearcut and partial-cut and uncut sites of boreal mixedwoods

Boreal mixedwoods are an important element and the most productive forest type in the Canadian boreal forests. However, they experience frequent disturbances. In order to better understand the responses of boreal mixedwoods to different combinations of anthropogenic and natural disturbances, we investigated the natural regeneration of boreal mixedwoods that were previously subjected to three different harvesting treatments (clearcut, partial-cut and uncut control) and naturally regenerated, but subsequently burnt by a severe natural fire 6 years later. The study was conducted 8 years following the fire. Significant interactions were found among harvesting method, species and block in several regeneration variables. There were a total of 12 woody species (trees and shrubs) regenerated, but not all the species were present in all the sites. In general, the species richness and species diversity of the new stands were lowest on clearcut sites while the differences between partial-cut and control varied with blocks. However, the combined total density for all species was lowest on uncut control sites. Density and regeneration index data show that trembling aspen was the predominant tree species in all stands except at one uncut control site where jack pine was the dominant species. The density of trembling aspen generally declined from clearcut to partial to the uncut control. Pincherry, beaked hazel and mountain maple were the dominant shrub species in the new stands, but no general patterns were found in terms of variations in density with harvesting methods for any of the shrub species. Jack pine and white birch were the tallest tree species in the clearcut treatment while white birch was taller than jack pine in the partial-cut and control. The results suggest that active measures are necessary to restore the complex structure of the initial mixedwoods.

Rhizosphere soil microbial index of tree species in a coal mining ecosystem

Microbial characterization of the tree rhizosphere provides important information relating to the screening of tree species for re-vegetation of degraded land. Rhizosphere soil samples collected from a few predominant tree species growing in the coal mining ecosystem of Dhanbad, India, were analyzed for soil organic carbon (SOC), mineralizable N, microbial biomass carbon (MBC), active microbial biomass carbon (AMBC), basal soil respiration (BSR), and soil enzyme activities (dehydrogenase, urease, catalase, phenol oxidase, and peroxidase). Among the tree species studied, Aegle marmelos recorded the highest value for MBC (590 mg kg −1), urease (190.5 μg NH 4 +-N g −1 h −1), catalase (513 μg H 2O 2 g −1 h −1), dehydrogenase (92.3 μg TPF g −1 h −1), phenol oxidase (0.057 μM g −1 h −1) and BSR/AMBC (0.498 mg CO 2-C mg biomass −1 day −1); Tamarindus indica for mineralizable N (69.5 mg kg −1); Morus alba for catalase (513 μg H 2O 2 g −1 h −1) and phenol oxidase (0.058 μM g −1 h −1); Tectona grandis for peroxidase (0.276 μM g −1 h −1), AMBC/MBC (99.4%), and BSR/MBC (0.108 mg CO 2-C mg biomass −1 day −1); Ficus religiosa for AMBC (128.4 mg kg −1) and BSR (12.85 mg CO 2-C kg −1 day −1); Eugenia jambolana for MBC/SOC (8.03%); Butea monosoperma for AMBC/SOC (1.32%) and Azadirachta indica for BSR/AMBC (0.1134 mg CO 2-C mg biomass −1 day −1). Principal component analysis was employed to derive a rhizosphere soil microbial index (RSMI) and accordingly, dehydrogenase, BSR/MBC, MBC/SOC, EC, phenol oxidase and AMBC were found to be the most critical properties. The observed values for the above properties were converted into a unitless score (0–1.00) and the scores were integrated into RSMI. The tree species could be arranged in decreasing order of the RSMI as: A. marmelos (0.718), A. indica (0.715), Bauhinia bauhinia (0.693), B. monosperma (0.611), E. jambolana (0.601), Moringa oleifera (0.565), Dalbergia sissoo (0.498), T. indica (0.488), Morus alba (0.415), F. religiosa (0.291), Eucalyptus sp. (0.232) and T. grandis (0.181). It was concluded that tree species in coal mining areas had diverse effects on their respective rhizosphere microbial processes, which could directly or indirectly determine the survival and performance of the planted tree species in degraded coal mining areas. Tree species with higher RSMI values could be recommended for re-vegetation of degraded coal mining area.

Genetic fingerprinting using AFLP cannot distinguish traditionally classified baobab morphotypes

Baobab (Adansonia digitata L.) is one of the predominant tree species in West African agroforestry systems. A local morphological classification system is used by farmers, identifying trees with desired or undesired combinations of traits. This study evaluates the genetic significance of these morphotypes by comparing local identification with AFLP marker information. Eight morphotypes were recognized by seven ethnic groups from Benin, Ghana and Senegal, among 182 sampled baobab trees. Five primer pairs were used for DNA fingerprinting, resulting in a total of 254 scored bands, of which between 94.1% and 100% was polymorphic within morphotypes. Generally, genetic fingerprinting did not correlate with the traditional morphological identification of Adansonia digitata. Probably, AFLP markers are not directly linked to the differences in phenotype or the traits used for the traditional classification are largely dependent on environmental factors. Since no genetic differentiation is found between the morphotypes, a morphotype-based approach in the collection of genetic variation for conservation programs is not advisable.

Can fog contribute to the nutrition of Chamaecyparis obtusa var. formosana? Uptake of a fog solute tracer into foliage and transport to roots

Yellow cypress (Chamaecyparis obtusa (Siebold & Zucc.) Endl. var. formosana (Hayata) Rehder) is the predominant tree species of Taiwan's nutrient-poor, mountain fog forests. Little is known about the potential contribution of solute uptake from fog to the overall nutrition of these trees. Shoots of yellow cypress seedlings were misted with artificial fog containing the tracer rubidium (Rb) in laboratory and field experiments to determine if there is solute uptake from the fog. After misting shoots for six weeks, substantial amounts of tracer were detected in unexposed roots by inductively coupled plasma mass spectroscopy bulk analysis. Possible routes of entry were examined by element imaging with energy dispersive X-ray analysis. Direct uptake of the tracer into leaves across the cuticle and epidermis was small, excluding this as the major uptake path. Accumulations of Rb were found on leaf surfaces along the edges of the leaves. The almost daily changes in fog coverage and air humidity may enhance the accumulation of fog solutes at leaf edges. Accumulation of Rb was also found in narrow clefts between opposite leaves and between the outermost and underlying alternating stacked leaves. The clefts provide a direct passage from the leaf surface to the space beneath the imbricate leaves and the underlying alternate leaves, possibly facilitating solute uptake from fog, which in turn may contribute to the nutrition of yellow cypress.

Forest canopy recovery from the 1938 hurricane and subsequent salvage damage measured with airborne LiDAR

The structure of a forest canopy often reflects its disturbance history. Such signatures of past disturbances or legacies can influence how the ecosystem functions across broad spatio-temporal scales. The 1938 hurricane and ensuing salvage operations which swept through New England represent the most recent large, infrequent disturbance (LID) in this region. Though devastating (downing ∼ 70% of the timber at Harvard Forest), the disturbance was not indiscriminate; it left behind a heterogeneous landscape comprised of different levels of canopy damage. We analyzed large-footprint LiDAR, from the Prospect Hill tract at Harvard Forest in central Massachusetts, to assess whether damage to the forest structure from the hurricane and subsequent timber extraction could be discerned after ∼ 65 years. Differences in LiDAR-derived measures of canopy height and vertical diversity were a function of the degree of damage from the 1938 hurricane and the predominant tree species which is, in part, a function of land use history. Higher levels of damage corresponded to slightly shorter canopies with a less even vertical distribution of return from the ground to the top. In addition, differences in canopy topography as revealed by spatial autocorrelation of canopy top heights were found among the damage classes. Less disturbed stands were characterized by lower levels of local autocorrelation for canopy height and higher levels of vertical diversity of LiDAR returns. These differences in canopy structure reveal that the forest tract has not completely recovered from the 1938 LID and salvage regime, which may have implications on arboreal and understory habitat and other ecosystem functions.

Neutral rhizoplane pH of local rice and some predominant tree species in South and Central Kalimantans: A possible strategy of plant adaptation to acidic-soil

To investigate the acid sulfate soil-adapting strategies of South Kalimantan local rice varieties, their rhizoplane pH was preliminarily examined using a glass-made micro-electrode. Although raw acid-sulfate soils in paddocks in South Kalimantan were generally pH 3.5-4.5 and sometimes pH 2.5, pH values of the rhizoplane of living roots directly measured by the microelectrode always converged to approximately 7.0 (variance 0.02-0.22, n=10). On the other hand, the pH of dead roots, which was measured after soil was thoroughly washed from the surface, was relatively low and often close to the soil pH itself. Similarly constant neutral rhizoplane pH was also observed in the major Central Kalimantan tree species, Cratoxyllum arborescens (upland) and Combretocarpus rotundatus (swampy forests). Whilst, two other predominant grasses, Xyris complanata and Imperata cylindrica, inhabiting acidic soils in upland and lowland, had relatively low rhizoplane pH (6.05 and 5.86, respectively), suggesting that these grasses have different strategies than the paddy rice varieties for adapting to acidic conditions. Rhizoplane bacteria are likely to be one of the factors for the maintenance of neutral rhizoplane pH. In fact, some Sphingomonas sp. raised medium pH, originally set at pH 4.0, to 5.5. These findings suggested the importance of cationic charge in the rhizoplane of local rice varieties for adapting to acid-sulfate soil, which is similar to strategy of some arboreal trees inhabiting acidic peat soil.

散居集落の景観保全に向けた屋敷林における住民意識及びその分布・植栽形態と景観施策に関する研究―岩手県胆沢町を事例として―

Isawa is a town in the Iwate prefecture, famous for its homestead woodlands which surround dispersed settlements. Despite its renown, it has been decreasing rapidly. A study was conducted on the following. The structures of the homestead woodlands, the residents' awareness of the woodlands and the policy of the local government to conserve the woodlands.In this district, the woodlands are primarily located in the northern and western sides of the houses to protect them from the wind and snow. The predominant tree species are the evergreen conifers such as Cryptomeria japonica. The structures of the woodlands were divided into four categories.Type I: The numbers of trees are less and usually planted in a single row where the low branches are pruned frequently.Type II: The numbers of trees are more than type I, and planted closely in multiple rows.Type II includes type II-1, where tree's height is higher than the roof, and type II-2, where tree's height is lower.The species of trees are less and usually limited to conifers as mentioned in Type I and II.Type III: The trees are planted in eastern side, in addition to the northern and western sides. Here, several broadleaved species of trees have been planted in addition to the conifers.There are a variety of trees, which include several broadleaved species, in addition to the conifers. The layer of trees between the arbor and shrub layers was missing. To increase the volume of homestead woodlands, the planting pattern determined by our investigations may be utilized as a reference. In addition, it may easily be promoted by seeking financial assistance from an organization. On the other hand, homesteads, which do not require such financial assistance, the maintenance and management options that would not destroy the landscape's function, were suggested within the tolerance level.Most residents are proud of the homestead woodlands. They are of the view that the woodlands have great value in making up the original landscape and have an addition role in the protection of houses from disasters. However, the younger generation displayed less interest than the elder generation.The town's government has been providing subsidies for the plantation of homestead woodlands, since 1996. The above categories indicate the values of homestead woodlands. These indexes may be useful in promoting the subsidy system.The homestead woodlands are decreasing rapidly throughout Japan. It is very important to raise this awareness and also improve the subsidy system. Furthermore, the total strategies to conserve the woodlands by land use and landscape regulations are still not in place. The local government must seriously consider these.

Prolonged diapause of specialist seed-feeders makes predator satiation unstable in masting of Quercus crispula.

Quercus crispula (= Q. mongolica var. grosseserrata) is the predominant tree species in cool temperate, mixed broadleaf/conifer forests in northern Japan. We compared 11 years of data on acorn production in a population of Q. crispula, with data on seed-insect populations, to try to answer the following questions: (1) Does Q. crispula show a regular pattern of masting? (2) How long do principal seed predators remain in diapause? (3) How do the seed predators affect the pattern of predator satiation? Q. crispula showed a tendency to alternate bearing, with significant synchrony between individual trees. The principal acorn-feeding insects ( Curculio spp. weevils), which infested 25%-70% of matured acorns, generally exhibited a prolonged diapause of 2 years. No significant negative relationship was found between the rate of injury by the weevils and the density of mature acorns, indicating that simple predator satiation fails due to the synchrony of the life-cycle of acorn-feeding insects and the periodical production of acorns. However, the rate of injury by the weevils was negatively correlated with the relative abundance of mature acorns to the number of weevil larvae that had matured 2 years previously. Thus, the proportion of sound acorns notably increased in a rich crop after a disturbance in alternate bearing. Prolonged diapause of specific seed predators is critical in determining the peak year of sound-seed production.

Ecophysiological adaptations of black spruce ( Picea mariana ) and tamarack ( Larix laricina ) seedlings to flooding

Black spruce (Picea mariana (Mill.) B.S.P.) and tamarack (Larix laricina (Du Roi) K. Koch) are the predominant tree species in boreal peatlands. The effects of 34 days of flooding on morphological and physiolog- ical responses were investigated in the greenhouse for black spruce and tamarack seedlings in their second growing season (18 months old). Flooding resulted in reduced root hydraulic conductance, net assimilation rate and stomatal conductance and increased needle electro- lyte leakage in both species. Flooded tamarack seedlings maintained a higher net assimilation rate and stomatal conductance compared to flooded black spruce. Flooded tamarack seedlings were also able to maintain higher root hydraulic conductance compared to flooded black spruce seedlings at a comparable time period of flooding. Root respiration declined in both species under flooding. Sugar concentration increased in shoots while decreasing in roots in both species under flooding. Needles of flooded black spruce appeared necrotic and electrolyte leakage increased over time with flooding and remained signif- icantly higher than in flooded tamarack seedlings. No visible damage symptoms were observed in flooded tamarack seedlings. Flooded tamarack seedlings devel- oped adventitious roots beginning 16 days after the start of flooding treatment. Adventitious roots exhibited significantly higher root hydraulic conductivity than similarly sized flooded tamarack roots. Flooded black spruce lacked any such morphological adaptation. These results suggest that tamarack is better able to adjust both morphologically and physiologically to prolonged soil flooding than black spruce seedlings.

Responses of black spruce (Picea mariana) and tamarack (Larix laricina) to flooding and ethylene.

Black spruce (Picea mariana (Mill.) BSP) and tamarack (Larix laricina (Du Roi) K. Koch) are the predominant tree species in the boreal peatlands of Alberta, Canada, where low nutrient availability, low soil temperature and a high water table limit their growth. Effects of flooding for 28 days on morphological and physiological responses were investigated in greenhouse-grown black spruce and tamarack seedlings in a growth chamber. Flooding reduced root hydraulic conductance, net assimilation rate and stomatal conductance, and increased water-use efficiency (WUE) and needle electrolyte leakage in both species. Although flooded black spruce seedlings maintained higher net assimilation rates and stomatal conductance than flooded tamarack seedlings, flooded tamarack seedlings were able to maintain higher root hydraulic conductance than flooded black spruce seedlings. Needles of flooded black spruce developed tip necrosis and electrolyte leakage after 14 days of flooding, and these symptoms were subsequently more prominent than in needles of flooded tamarack seedlings. Flooded tamarack seedlings exhibited no visible injury symptoms and developed hypertrophied lenticels at their stem base. Application of exogenous ethylene resulted in a significant reduction in net assimilation, stomatal conductance and root respiration, whereas root hydraulic conductivity increased in both species. Thus, although flooded black spruce seedlings maintained a higher stomatal conductance and net assimilation rate than tamarack seedlings, black spruce did not cope with the deleterious effects of prolonged soil flooding and exogenous ethylene as well as tamarack.