Larger Basal Area Research Articles

Woody Species Composition Analysis of Shawo Sacred Forest, Ethiopia

In sacred forests of indigenous communities, landscapes are deemed sacred and are protected through social norms and spiritual values. The main objective of this study was to analyze the woody species composition of Shawo forest and explore the traditional governing systems that safeguard the sacred forest up to the present. Systematic sampling method was used to collect data. Accordingly, 42 quadrats each with 400 m2 (20 m X 20 m) was laid along the 14 transect lines. All woody plant species were collected and identified in each of these quadrats. Vegetation parameters such as DBH an Height of each quadrat were recorded. Interview and group discussion were held with local community to gather socio-cultural information. From the result, 16 plant species were found. The average plant density was 499 individual ha-1 with DBH and H value of 9.21 cm and 10.43 m respecitively.. The maximum mean plant height was 39.43 m (Syzygium guineense).The total basal area of all plant species was found to be 56.1 m2.ha-1. From the total plant species of Shawo forest Syzygium guineense has the largest basal area 35.77 m2.ha-1 (63.77%) occurring in all 42 plots. The most important plant species of Shawo forest was Syzygium guineense with important value index (IVI) of 151.7 contributing to 50.57% of total IVI. For future sustainability of Shawo forest, community traditional conservation practices should be appreciated and supported.

Struktur Floristik Hutan di Kawasan Lindung Sempadan Sungai dalam Areal Hutan Tanaman Industri

This study was carried out in riparian conservation forests within a monospecific pulpwood estate in Sorek,Pelalawan District, Riau. The remaining natural forests comprised lowland rainforest (at Sei Buluh and Tolamriversides), mixed swamp forest (at Telayap riverside), and pole forest (at Rangsang riverside). The objective of thecurrent study was to describe the floristic structure of each forest type at the conservation areas in concern.Fifteen transects (width of 20 m) were established at all sites with a total length of 8.080 m. Quadrates plots of 20x 20 m were established with continue on these transect for tree sampling (dbh > 20 cm) and smaller quadrates(10 x 10 m) were nested on each one of the former for pole sampling (dbh 10 – 20 cm). The parameters used in thisstudy were Importance Value (IV), species richness (Margalef Index = R1 and Menhinick Index = R2), and Diversity Index (Shannon = H’ and Simpson = D). Results showed that in tree stratum, the largest basal area (11.25 m2ha-1) and the highest diversity was found at Telayap’s riverside (H’ = 3.70 and D = 0.98). Species richness was most profound at Tolam riverside (R1 = 10.43 and R2 = 2.83). Rangsang’s riverside possessed the highest tree density (105 individuals ha-1) but with the smallest dbh (26.5 cm). This forest was a peat-swamp forest predominating by bintangur (Calophyllum pulcherimum). At the pole stratum, the largest basal area (7.00 m2ha-1) and the highest diversity was found at Tolam riverside (H’ = 3.39 and D = 0.96). Species richness was most profound at Telayap’s riverside (R1 = 8.89 and R2 = 2.64). The highest pole density (380 individuals ha-1) was observed at Sei Buluh’s riverside, in which mempening (Quercus lucida Roxb.) was predominating. Acacia mangium was establishing very well at all sites, indicating its adaptability and potentially invasive feature.

Impact of Eidolon helvum on roost trees on UENR campus

Four sample plots, each of size 20m by 20m were systematically distributed in two strata (i.e. two plots in bat-occupied zone andthe remaining two plots in bat-unoccupied zone, to serve as control units). Using six (20m × 20m) sample plots each, basal area,canopy, and heights of trees with DBH 1m were measured. Fourteen individual trees were recorded in the bat-unoccupied zone,resulting in only seven tree species. On the other hand, 16 tree species, corresponding to a total of 25 trees were recorded in thebat occupied zone. Albizia zygia, Antiaris toxicaria, Azadiractha indicia, Holarrhena floribunda, Morinda lucinda, and Sterculiatragacantha were common to both zones. The Shannon Wiener species diversity index was found to be higher (H1=1.92) in batoccupied zones and lower (H1=1.45) in bat-unoccupied zone. Estimates of tree basal area and tree height were much higherin bat occupied zones compared to bat-unoccupied zones. (Mann-Whitney U test: U = 573.0, p < 0.05), tree basal area (U= 674.0, p < 0.05), tree height (U = 632.0, p < 0.05) and tree canopy cover (U = 329.0, p < 0.05). Holarrhena floribunda(0.34 m2/h) and Ceiba pentandra (0.22m2/ha) contributed the largest basal area (32.94% of the total basal area) whilst Sennasiamea (0.01m2/ha) and Tectona grandis (0.01m2/ha) yielded the smallest basal area (1.17%). In general, bats seem to greatlypatronize areas with higher densities of tall trees than relatively open areas with shorter trees.

Implications of Diameter Caps on Multiple Forest Resource Responses in the Context of the Four Forests Restoration Initiative: Results from the Forest Vegetation Simulator

Meeting multiple resource objectives, such as increasing resilience to climate change, while simultaneously increasing watershed health, conserving biodiversity, protecting old-growth, reducing the risk of catastrophic wildfire, and promoting ecosystem health, is paramount to landscape restoration. Central to public land management efforts in the West is the widespread adoption of size-prohibited cutting of “large” trees, a limitation referred to as a “diameter cap.” In this study, we used the most commonly proposed prescription for the Four Forest Restoration Initiative in northern Arizona to explore the implications of diameter caps for multiple resource responses through the use of model simulations. We found that implementing progressively smaller caps in southwestern ponderosa pine may result in relatively similar live tree densities, canopy cover, and large snag densities but higher basal areas, mean tree size, torching indices, and scenic beauty with lower water yield and herbaceous production. When diameter cap scenarios are compared, tradeoffs exist, and no single metric is suited for overall scenario evaluation.

Estrutura do componente arbustivo-arbóreo da vegetação em duas áreas de caatinga, no município de Floresta, Pernambuco

Avaliaram-se a composição e estrutura do componente arbustivo-arbóreo da vegetação de duas áreas de caatinga com diferentes histórias de uso, em Floresta, PE. Foram avaliadas 60 parcelas de 20 x 20 m, sendo 40 em área de vegetação secundária, 22 anos após o corte raso (Área I); e 20 parcelas em área com vegetação conservada (Área II). Foi feita a identificação botânica e medidas a circunferência à altura do peito (CAP) e a altura das árvores com CAP > 6,0 cm, estimando os parâmetros de estrutura horizontal e índices de riqueza e diversidade. A vegetação secundária apresentou maior riqueza de espécies, diferindo quanto à estrutura fitossociológica e fisionomia da vegetação conservada. Nas duas áreas, a espécie de maior Valor de Importância foi Poincianella bracteosa, cuja dominância foi maior na Área I, onde Pityrocarpa moniliformis, Piptadenia viridifolia, Senna spectabilis e Croton blanchetianus foram exclusivas. Croton rhamnifolius, Manihot glaziovii e Myracrodruon urundeuva, presentes em ambas as áreas, tiveram maior importância relativa na área conservada. Na área conservada, a vegetação apresentou área basal, altura média e máxima maiores do que na área perturbada, mostrando que a estrutura da vegetação com 22 anos ainda estava em desenvolvimento. Tomando como referência a área basal da Área II e o incremento estimado na área de vegetação secundária, a regeneração em áreas desmatadas exigiria período superior a 40 anos para reestabelecer a estrutura original.

Long-term development of nursing mixtures of Sitka spruce and larch species in an experiment in northern Scotland

Aim of the study: An experiment was established in 1966 to compare the growth and development of 50: 50 mixtures of Sitka spruce (Picea sitchensis) with either Japanese larch (Larix kaempferi) or tamarack (L. laricina) with that found in pure plots of Sitka spruce. The site was one of moderate nitrogen availability where the presence of heather (Calluna vulgaris) could be expected to limit the growth ofSitka spruce.Area of the study: North-east Scotland.Material and methods: There were different patterns of spruce growth in the pure plots and in the mixtures, with faster spruce growth in mixture in the years approaching and immediately following canopy closure (i.e. ages 15-25). Foliage analysis suggested that this was linked with improved nitrogen status of spruce trees in the mixed compared to the pure plots.Main results: At years 20 and 25 there were significant differences in height, diameter, and basal area between treatments, with the largest basal area being found in the Japanese larch/Sitka spruce mixtures, indicative of overyielding in the mixed plots. However, when the experiment was clearfelled at 41 years of age, all treatments had self-thinned to produce spruce dominated stands of similar height with only an occasional larch tree surviving in plots that were originally 50:50 mixtures.Research highlights: There were no differences between treatments in basal area, harvested volume or sawlog outturn after 41 years. These results can be interpreted as showing facilitation between the larch and the spruce during the establishment phase followed by competition for light once canopy closure had occurred.Keywords: Mixed stand dynamics; facilitation; nitrogen status; product outturn.

Cambios estacionales acelerados en comunidades boscosas debidos al aumento en la humedad del suelo después de la construcción de una represa

Local changes caused by dams can have drastic consequences for ecosystems, not only because they change the water regime but also the modification on lakeshore areas. Thus, this work aimed to determine the changes in soil moisture after damming, to understand the consequences of this modification on the arboreal community of dry forests, some of the most endangered systems on the planet. We studied these changes in soil moisture and the arboreal community in three dry forests in the Araguari River Basin, after two dams construction in 2005 and 2006, and the potential effects on these forests. For this, plots of 20 m x 10 m were distributed close to the impoundment margin and perpendicular to the dam margin in two deciduous dry forests and one semi-deciduous dry forest located in Southeastern Brazil, totaling 3.6 ha sampled. Besides, soil analysis were undertaken before and after impoundment at three different depths (0-10, 20-30 and 40-50 cm). A tree (minimum DBH of 4.77 cm) community inventory was made before (TO) and at two (T2) and four (T4) years after damming. Annual dynamic rates of all communities were calculated, and statistical tests were used to determine changes in soil moisture and tree communities. The analyses confirmed soil moisture increases in all forests, especially during the dry season and at sites closer to the reservoir; besides, an increase in basal area due to the fast growth of many trees was observed. The highest turnover occurred in the first two years after impoundment, mainly due to the higher tree mortality especially of those closer to the dam margin. All forests showed reductions in dynamic rates for subsequent years (T2-T4), indicating that these forests tended to stabilize after a strong initial impact. The modifications were more extensive in the deciduous forests, probably because the dry period resulted more rigorous in these forests when compared to semideciduous forest. The new shorelines created by damming increased soil moisture in the dry season, making plant growth easier. We concluded that several changes occurred in the T0-T2 period and at 0-30 m to the impoundment, mainly for the deciduous forests, where this community turned into a "riparian-deciduous forest" with large basal area in these patches. However, unlike other transitory disturbances, damming is a permanent alteration and transforms the landscape to a different scenario, probably with major long-term consequences for the environment.

Tree species diversity and related mechanism in an evergreen broad-leaved forest in Ailao Mountains, Yunnan, China

There is no enough data or evidence to reach a firm conclusion for tree species diversity and related mechanism in an evergreen broad-leaved forest in Ailao Mountains, Yunnan, China. A 6-hm2 plot was established in Ailao Mountains State Nature Reserve for the purpose of monitoring long-term dynamics of tree populations. All free-standing trees with diameter at breast height (DBH) ≥ 1 cm were tagged, mapped, measured (girth) and identified to species in the plot. The spatial distribution patterns of four dominant canopy tree species in the plot were analyzed using a point pattern analysis Ripley’s L-function. A total of 12131 free-standing individuals with DBH ≥ 1 cm were recorded in the plot, including 68 species belonging to 49 genera and 25 families. Lithocarpus hancei had the largest basal area and the largest importance value. Camellia forrestii, an understory tree species was ranked the second in terms of importance value, although it showed the highest abundance (1712 individuals). The four canopy dominant species had a large number of seedlings and saplings and tend to be patchily distributed. And the spatial distributions of 26 tree species with ≥40 individuals was examined at each life history stage (diameter at breast height ≥1 cm), and 37 of 57 life history stages showed aggregated distribution pattern. It showed that it may be not density dependence but habitat heterogeneity as a prevalent mechanism for regulating the population spatial structure of most tree species in the subtropical forest studied here. Key words: Evergreen broad-leaved forest, habitat heterogeneity, spatial distribution pattern, tree species diversity.

Characteristics of Norway spruce trees (Picea abies) surviving a spruce bark beetle (Ips typographus L.) outbreak

The characteristics of spruce individuals, which survived a massive bark beetle outbreak, were compared with the characteristics of neighbouring attacked trees in Sumava National Park (Czech Republic). Selected parameters related to crown geometry, stand conditions and distances between trees were measured or estimated. Significant differences were found between the surviving trees and the neighbouring trees attacked by I. typographus. Trees with a higher level of stem shading (longer crown length) tended to survive. The attacked trees were usually located in areas with larger basal area, especially southwards from them. A shorter distance to a previously attacked tree increased the probability of additional attack. Spruce trees with more progressive crown structure transformation (primary structure defoliation) were significantly more frequently attacked by spruce bark beetle. Superior and taller trees had a clearly longer life expectancy than dominant ones. These results show that the attack of trees by bark beetle can be predicted to a certain degree, which can be used in management of endangered spruce forests.

Soil Fertility Status under Different Tree Cropping System in a Southwestern Zone of Nigeria

Tree cropping has been known to bring about changes in edaphic component among other components of the ecosystem through their interactions with the soil and soil faunas. Premised on this, this study assessed the effects of sole cropping of teak and intercropping of cocoa and kola on the soil fertility status. The study was carried out using stratified-randomed sampling technique for the study plots in all the sampling sites. Three sampling sites consisting of four (4)-4oo m2 sampling plots each were established in which vegetation and some soil parameters were assessed. Results analysis showed that the synergistic interaction of leaves decomposition of cocoa and kola improved the organic matter content of the soil under the cocoa/kola site. Considerable improvement in soil fertility was enjoyed in the cocoa/kola site due to the large girth sizes and basal area of trees present in the cocoa/kola site while soil under the sole cropping of teak was impoverished. The degradation effects was due to the high rate of nutrient uptake of the teak, organic matter content was high in the forest site (9.12%) and cocoa/kola site (7.34) while the least was in the teak site (3.04%). A very strong correlation existed between organic matter content and some vegetation parameters.

Spatial pattern of central African rainforests can be predicted from average tree size

When considering all trees irrespective of their species, natural tropical rain forests typically exhibit spatial patterns that range from random to regular. The regularity is often interpreted as a footprint of tree competition. Using 23 permanent sample plots totalling 61 ha in the rain forests of central Africa, we characterized their spatial patterns and modelled those that exhibited regularity by a Strauss point process. This Strauss process is obtained as a Markov point process whose interaction function is an exponential function of a competition index commonly used in forestry. The parameter of this Strauss process characterizes the strength of competition. The 23 plots in central Africa differed in tree density and basal area, and could be discriminated depending on the type of spatial patterns: plots having a large basal area with respect to their density had a non regular pattern, whereas those having a small basal area with respect to their density had a regular pattern. For those plots that exhibited regularity, average tree size could be used to predict the strength of competition. The parameter of the Strauss process was significantly related to the average size by a linear relationship, such that competition decreases as average tree size increases. This relationship extrapolated to a null value of the Strauss parameter when average tree size reaches 32 cm in diameter. This relationship between average tree size and spatial pattern is a testable feature for future studies on the relationship between competition and spatial pattern in natural forests.

A comparison between various definitions of forest stand height and aerodynamic canopy height

A consistent measure of forest canopy height is required for among-site comparisons of meteorological properties and for comparison of model results such as distributions of wind and other scalars calculated by large eddy simulations with observations. The aerodynamic canopy height has been proposed as a useful measure of canopy height, which is determined by micrometeorological methods without depending on stand inventory data. However, the aerodynamic canopy height is obtainable only if the necessary meteorological instruments are installed. In this study, we explored an alternative measure of forest canopy height based on tree inventory data. When cumulative trunk basal area from the shortest tree is plotted against corresponding individual tree height, it shows a sigmoidal curve with its inflection point occurring at a height class. The above-ground height of this inflection point (hereafter cumulative basal area inflection (CuBI) height) is defined as forest canopy height, as many tall trees with relatively large basal area belong to this height class. The difference between the aerodynamic canopy height and the CuBI height was always smaller than 12%, whereas the differences exceeded 20% for at least one of the forests when canopy height was determined using alternate methods. This suggests that, unlike other canopy height definitions, CuBI height is a consistent index of the aerodynamic canopy height, little affected by criterion of the trees composing the upper canopy or by the presence/absence of many shorter understory trees. Because chronological changes in size-structure of tree height and trunk diameter have long been studied for many forests, CuBI height may be used as an index of chronological change in the aerodynamic canopy height.

Transpiration and hydraulic traits of old and regrowth eucalypt forest in southwestern Australia

We tested the hypothesis that overstorey of eucalypt forest dominated by tall, large diameter trees uses less water than regrowth stands in the high rainfall zone (>1100 mm year −1 ) of the northern jarrah ( Eucalyptus marginata ) forest in southwestern Australia. We measured leaf area, cover, sapwood area and sapwood density at three paired old and regrowth stands. We also measured sapflow velocity at one paired stand (Dwellingup) from June 2007 to October 2008. Old stands had more basal area but less foliage cover, less leaf area and slightly thinner sapwood. The ratio of sapwood area to basal area decreased markedly as tree size increased. Sapwood area of the regrowth forest stands (6.6 ± 0.30 m 2 ha −1 ) was nearly double that of the old stands (3.4 ± 0.17 m 2 ha −1 ), despite larger basal area at the old stands. Leaf area index of the regrowth stands (2.1 ± 0.26) was only one-third larger than that at the old stands (1.5 ± 0.15); hence, the ratio of leaf area to sapwood area was larger in old stands than in regrowth stands (0.45 ± 0.022 m 2 cm −2 versus 0.32 ± 0.045 m 2 cm −2 ). Our results are consistent with theories that trees have evolved to optimize carbon gain rather than maintain stomatal conductance. Neither sapwood density (540–650 kg m −3 ) nor sap velocity differed greatly between regrowth and old stands. At the old forest site, daily transpiration rose from 0.5 mm day −1 in winter to 0.9 mm day −1 in spring–summer, compared to 0.9 mm day −1 and 1.8 mm day −1 at the regrowth site. Annual water use by the overstorey trees was estimated to be ∼230 mm year −1 for the old stand and ∼500 mm year −1 at the regrowth stand, or 20% and 44% of annual rainfall. The overwhelming role of stand sapwood area in determining stand water use, combined with the marked changes in the ratio of sapwood area to basal area with tree age and size, suggest that stand overstorey structure can be managed to alter overstorey water use and catchment water yield. Silviculture to promote old-forest-like attributes may be a viable means of delivering multiple water and conservation benefits.

Importance des sites sacrés pour la conservation des forêts-galeries au Centre-Bénin

Les mares, bassins ou sites sacrés de forêtsgaleries le long des cours d'eau, encore appelés Íbú ódó en langue Tchabè, sont respectés par les communautés Tchabè le long des fleuves Ouémé et Okpara au Centre-Bénin (Afrique de l'Ouest). Le caractère sacré de ces sites et points d'eau a un impact évident sur la conservation de la biodiversité, à travers la prohibition de l'utilisation des poisons pour la pêche, de la pollution des eaux, l'interdiction de l'élevage, les défrichements dans leur voisinage immédiat, etc. La structure et la diversité des forêts-galeries et Íbú ódó ont été examinées dans trois sites différents (Djabata, Idadjo et Monka) de forêts-galeries adjacents à des sites et points d'eau sacrés. En outre, les caractéristiques des forêts-galeries ont été analysées du point de vue des différents modes d'utilisation et de gestion des terres, en zones agricole, domaines utilisés par les villages et sites sacrés des religions traditionnelles. La diversité des ligneux (dbh 10 cm) est plus élevée dans les sites des forêts sacrées, tandis que la surface terrière est plus grande dans les sites à forte emprise humaine ou adjacents aux Íbú ódó. Sur le plan floristique, les forêts-galeries les plus éloignées des villages sont les plus diversifiées, avec les plus grandes surfaces terrières. L'enquête ethnobotanique auprès des anciens et des chefs chasseurs a révélé l'importance culturelle et la diversité des ressources des sites de forêtsgaleries sacrés. Les Íbú ódó sont respectés par tous les villageois y compris les immigrants et colons agricoles non Tchabè. Les fonctions des écosystèmes riverains (telles que brisevent, fertilité des sols, sites privilégiés de chasse) sont reconnues et valorisées par les populations riveraines. La présente étude recommande d'inclure les sites sacrés de forêts-galeries dans une stratégie de gestion durable du bassin du fleuve Ouémé, afin d'inverser la destruction de la végétation et de préserver la diversité des forêts-galeries. C'est une nécessité pour un contrôle efficace des inondations et la conservation de la biodiversité au Centre-Bénin. (Résumé d'auteur)

Effect of harvesting, vegetation structure and composition on the abundance and demography of the land crab Cardisoma guanhumi in Puerto Rico

Cardisoma guanhumi is the focus of an important artisanal fishery in Puerto Rico. Data on land crab landings point towards a dramatic decline in their abundance. This is cause for concern given the intrinsic value of the fishery and the important role these crabs play in coastal ecosystems. In this paper we examine the effect of harvesting and habitat quality on the abundance, survival, and size structure of C. guanhumi. To accomplish this we conducted a capture-mark-recapture study for a period of 18 months at three localities with minimal or no harvesting, and three with intense harvesting. Habitat quality at the six study sites was assessed by measuring vegetation composition-structure and litter biomass. We also conducted a leaf consumption experiment to evaluate leaf litter selectivity and limitation. Mean crab abundance differed significantly among sites, and this variation was significantly explained by differences in crab survival among sites. Sites with less harvesting tended to have higher survivorship and more crabs than sites where harvesting took place. Crabs mean size differed among study sites and was inversely related to abundance. Vegetation composition and structure, leaf litter standing stock and leaf-litter consumption differed among study sites. However, only some of these habitat characteristics are directly related to crab abundance or demography. There is a tendency for sites with a high leaf litter standing stock and large basal area to have the largest crabs but in low abundance. This study shows that C. guanhumi populations are very sensitive to increases in mortality that result from harvesting, and that the historical decline in abundance of this crab in Puerto Rico can be explained, in part, by an increase in trapping effort. Our results also indicate that C. guanhumi is a very plastic species, capable of occupying diverse types of coastal forests and a leaf litter generalist.

Influence of stand density and soil treatment on the Spanish Black Pine (Pinus nigra Arn. ssp. Salzmannii) regeneration in Spain

Satisfactory results relating to the natural regeneration of the Spanish black pine (Pinus nigra Arn ssp. salzmannii) is generally difficult to achieve. The natural regeneration of this pine was studied comparing two types of soil treatment and various overstory densities in six experimental forests. These studies were conducted from 1999 to 2002 and seed rain and germination, as well as seedling survival were observed in a number of specific plots: Brushing, scalping and control plots. In addition various overstory densities were used (measured as base area (square m/ha). Soil and air temperature together with soil moisture were continuously recorded throughout this summer period. The results showed that seed germination was higher in plots using the scalping technique, as opposed to the brushed or controlled plots. The best seedling survival percentage was found in scalped plots together with a larger basal area. It was also found that seedling survival was lower during the first year than during the second one. The results have practical implications for management of Spanish black pine forests as well as valuable information which could improve the conditions for regeneration.

Caracterización forrajera de un sistema silvopastoril de vegetación secundaria con base en la aptitud de suelo

Tree and shrub forage production were evaluated during the dry season in three soil within a silvopastoral system (SPS) complementary to traditional, local cattle systems in Yucatan, Mexico. Soils were Epileptic cambisol (CMlep, 24 %), Endoskelectic cambisol (CMnsk, 21.3 %) and Rodic luvisol (LVro, 28.4 %). Three, 100 m2 quadrants were set in each soil and vegetation with >1.0 cm maximun tree diameter at breast height inventoried in each quadrant. Experimental design was a stratified block arrangement with each soil being a block. Nine forage species were identified within the SPS. Bauhinia divaricata was the most abundant overall with 1,148 individuals and had the largest population (577 individuals) in the LVro. Piscidia piscipula (n= 495) had the largest basal area (1.8 m2) of the forage species. After standardization cut, only three species produced new shoots: Leucaena leucocephala, P. piscipula and B. divaricada. Considering these three species, the highest forage yield was observed in the CMlep. In this soil, L. leucocephala produced higher amounts of DM per plant than B. divaricata and P. piscipula. L. leucocephala and P. piscipula had better overall yield in the CMlep. B. divaricata did not perform differently in the three studied soils but had greater yield, better cut response and a higher number of plants than L. leucocephala and P. piscipula. These three species are potentially useful as forage producers during the dry season and their yields could be improved by considering regional pedodiversity.

Characterizing land-use diversity in village landscapes for sustainable mountain development: a case study from Indian Himalaya

This study aimed to analyze the ecological, socio-economic and policy implications of land-use diversity in a traditional village landscape (900–1,000 m amsl.) in the Garhwal region of Indian Himalaya. The village landscape was differentiated into three major land-use types viz., forests, settled agriculture and shifting agriculture. Settled agriculture was further differentiated into four agroecosystem types viz., homegarden system (HGS), rainfed agroforestry system (RAS), rainfed crop system (RCS) and irrigated crop system (ICS), and shifting agriculture system (SAS) was differentiated into different stages of a 4-year long cropping phase and a 7-year long fallow phase, and forests into Community Forests (CF) and Reserve Forests (RF). HGS is the most productive agroecosystem, with soil organic carbon and nutrient concentrations significantly higher than all other forest/agricultural land-uses. Farmers capitalize upon crop diversity to cope with the risks and uncertainties of a monsoon climate and spatial variability in ecological factors influencing productivity. The SAS, a land-use adopted as a means of acquiring inheritable rights over larger land holdings provided in the policies during the 1890s, is less efficient in terms of land productivity than the traditional RAS and HGS but is maintained for its high labour productivity coupled with availability of high-quality fuelwood from fallow vegetation. Dominance of fodder trees in the RAS seems to derive from policies causing shortage of fodder available from forests. Cultural norms have favoured equity by allowing hiring of labour only from within the village community and income from non-timber forest products only to the weaker section of the society. Conversion of rainfed to irrigated cropping, a change facilitated by the government, improves agricultural productivity but also increases pressure on forests due to higher rates of farmyard manure input to the irrigated crops. Existing forest management systems are not effective in maintenance of a large basal area in forests together with high levels of species richness, soil fertility and resistance to invasive alien species Lantana camara. Farmers have to spend huge amount of labour and time in producing manure, managing livestock and other subsidiary farm activities. Interlinkages among agriculture, forests and rural economy suggest a need of replacing the present policies of treating agricultural development, forest conservation and economic development as independent sectors by an integrated sustainable development policy. The policy should promote technological and institutional innovations enabling parallel improvements in agricultural productivity and functions of forest ecosystems.

Evergreen sclerophyllous <i>Quercus</i> forests in northwestern Yunnan, China as compared to the Mediterranean evergreen <i>Quercus</i> forests in California, USA and northeastern Spain

Abstract. Evergreen sclerophyllous Quercus forests in NW Yunnan (China) were studied and compared with the Mediterranean evergreen sclerophyllous Quercus forests in central coastal California (USA) and Catalonia (NE Spain). Forests of Q. aquifolioides, Q. pannosa, Q. longispica of NW Yunnan, Q. agrifolia of California and Q. ilex of NE Spain were analyzed as representative communities. The similarities and differences at the community level in the contemporary vegetation of the sclerophyllous Quercus forest found in the three regions are clarified. The general patterns of the evergreen Quercus forest in the three regions were similar, though different assemblages of species were involved. The species diversity in all three regions was rather low. The species richness did not significantly differ among the forests, although in the Q. longispica forest it is somewhat higher than the others. The three representative species of evergreen Quercus in NW Yunnan reached the greatest maximum height, while Q. agrifolia of California had the largest basal area per ha. The Q. ilex forest of Spain had the lowest values for maximum tree height and dbh and the highest density per ha. Frequency of dbh size classes indicated that Q. aquifolioides, Q. pannosa, and Q. agrifolia had potentially good regeneration of the sporadic type with highest values for the intermediate size classes, and the regeneration of Q. longispica and Q. ilex was strong as indicated by a reverse-J pattern. Still, in each area, most regeneration was from sprouting. In all three regions the evergreen Quercus species have adapted to environmental changes, for instance by development of sprouting and rooting abilities to resist drought, cold conditions and various disturbances. The evergreen Quercus forests in NW Yunnan were structurally more similar to the Q. agrifolia forest of central coastal California than to the Q. ilex forest of NE Spain.

Determinants of litter accumulation and the abundance of litter-associated microarthropods in bird's nest ferns (Asplenium nidus complex) in the forest of Yambaru on Okinawa Island, southern Japan

We studied the distributional pattern of bird's nest ferns (Asplenium nidus complex) and the factors that determined litter accumulation and the abundance of litter-associated microarthropods in the ferns in the forest of Yambaru on the northern part of Okinawa Island, southern Japan. We located 53 bird's nest ferns (41 ferns on 27 live trees of 13 species, and 12 on 5 dead trees) in a ca. 4-ha plot, collected litter samples from 37 ferns on 25 live trees, and then extracted a total of 11205 microarthropods (Acari and Collembola) from all the litter samples. The ferns preferred concave slopes and tended to be distributed on the tree species that had the typical characteristics of high population density and/or large basal area in the forest. The ferns were usually established on large trees [≥10m high or ≥20cm diameter at breast height (DBH)], although the number and size of the ferns were not related to the size of the host trees. The amount of litter accumulated in the ferns was correlated neither with the size (height and DBH) of the host tree nor with the height and position of the ferns. The amount of accumulated litter had a significant positive correlation only with fern size; this might have caused the positive correlations between fern size and the abundance of litter-associated microarthropods and the number of species of oribatid mites in the ferns.