Growth Of Tree Species Research Articles

Effect of neighborhood competition on key tree species growth in broadleaved-Korean pine mixed forest in Changbai Mountain, China.

Competition is the main factor affecting the growth, morphology and death of trees in fore-sts. The analysis of individual competition can reflect the characteristics of interaction among individuals and their interaction ranges, which is important for reducing individual competition and promoting tree growth. To understand the effects of competition on tree growth in broad-leaved Korean pine forest, based on Hegyi single-tree competition index and neighborhood analysis method, we explored the neighborhood radius of competition for five key tree species, i.e. Pinus koraiensis, Tilia amurensis, Fraxinus mandshurica, Quercus mongolica and Ulmus japonica (80% of basal area at breast height in total), and analyzed the effects of competition on the growth and death of the key tree species. The results showed that the neighborhood radius of single-tree competition of four tree species, P. koraiensis, T. amurensis, F. mandshurica and Q. mongolica was 11 m, while that of U. pumila was 13 m. The single-tree competition intensity for all five key tree species was negatively correlated with the logarithm of its growth increment, and positively correlated with the size of individual trees. The relative importance of competition intensity on tree growth decreased with tree growth. Neighborhood competition significantly increased tree mortality. Our results revealed the effects of neighborhood competition on the growth and survival of the key tree species at different developmental stages in broad-leaved Korean pine forests in Changbai Mountain. The results are instructive to the adjustment of competitive environment and the improvement of productivity of key tree species in broad-leaved Korean pine forests.

Wood Growth in Pure and Mixed Quercus ilex L. Forests: Drought Influence Depends on Site Conditions.

Climate response of tree-species growth may be influenced by intra- and inter-specific interactions. The different physiological strategies of stress response and resource use among species may lead to different levels of competition and/or complementarity, likely changing in space and time according to climatic conditions. Investigating the drivers of inter- and intra-specific interactions under a changing climate is important when managing mixed and pure stands, especially in a climate change hot spot such as the Mediterranean basin. Mediterranean tree rings show intra-annual density fluctuations (IADFs): the links among their occurrence, anatomical traits, wood growth and stable isotope ratios can help understanding tree physiological responses to drought. In this study, we compared wood production and tree-ring traits in Quercus ilex L. dominant trees growing in two pure and two mixed stands with Pinus pinea at two sites in Southern Italy, on the basis of the temporal variation of cumulative basal area, intrinsic water use efficiency (WUEi), δ18O and IADF frequency in long tree-ring chronologies. The general aim was to assess whether Q. ilex trees growing in pure or mixed stands have a different wood production through time, depending on climatic conditions and stand structure. The occurrence of dry climatic conditions triggered opposite complementarity interactions for Q. ilex growing with P. pinea trees at the two sites. Competitive reduction was experienced at the T site characterized by higher soil water holding capacity (WHC), lower stand density and less steep slope than the S site; on the opposite, high competition occurred at S site. The observed difference in wood growth was accompanied by a higher WUEi due to a higher photosynthetic rate at the T site, while by a tighter stomatal control in mixed stand of S site. IADF frequency in Q. ilex tree rings was linked to higher WUEi, thus to stressful conditions and could be interpreted as strategy to cope with dry periods, independently from the different wood growth. Considering the forecasted water shortage, inter-specific competition should be reduced in denser stands of Q. ilex mixed with P. pinea. Such findings have important implications for forest management of mixed and pure Q. ilex forests.

Ecophysiological response of early stage Albizia lebbeck to cadmium toxicity and biochar addition

Cadmium (Cd) toxicity is among the most prominent issues regarding land degradation. Traditional approaches for soil remediation are not effective. However, phytoremediation is described as the most efficient, economical, and sustainable approach to combat with terrestrial heavy metal pollution. Moreover, if phytoremediation is used in combination with soil amendment, its effectiveness can be increased several folds. Among soil amendments, biochar is considered the best amendment due to its potential for remediation and plant growth. The objective of this study was to determine the phytoremediation potential of Albizia lebbeck in Cd-contaminated and biochar-amended soils. A pot experiment was planned to test the ecophysiological response and Cd uptake of 3-month-old uniform-sized Albizia lebbeck seedlings. Cadmium was induced in soil through irrigational water at the rate of 25 mg/L. Two concentrations of biochar were used: B1 (3%) and B2 (6%). A total of six treatments were applied: Cd0B0 (T1), Cd0B1 (T2), Cd0B2 (T3), Cd1B0 (T4), Cd1B1 (T5), and Cd1B2 (T6), where, Cd0 and B0 designate the control treatment. The plants were harvested after 4 months of growth in the soil with amendments. The maximum growth and gas exchange characteristics were showed by the plant of T3. Cadmium toxicity reduced the growth and gas exchange characteristics to a great extent. Plants of T4 showed the minimum growth compared to the other amendments. The addition of 6% biochar in Cd-contaminated soil (T6) resulted in the decent increase in the growth of plants. The maximum root length (67.18 cm) and shoot length (80.06 cm) were observed in the plants of T3, whereas, the minimum root length (13.94 cm) and shoot length (35.03 cm) were observed in the plants of T4. This study suggests that biochar can be used to enhance the growth of agroforestry tree species like Albizzia lebbek in Cd-contaminated soils.

Without management interventions, endemic wet-sclerophyll forest is transitioning to rainforest in World Heritage listed K'gari (Fraser Island), Australia.

Wet‐sclerophyll forests are unique ecosystems that can transition to dry‐sclerophyll forests or to rainforests. Understanding of the dynamics of these forests for conservation is limited. We evaluated the long‐term succession of wet‐sclerophyll forest on World Heritage listed K'gari (Fraser Island)—the world's largest sand island. We recorded the presence and growth of tree species in three 0.4 hectare plots that had been subjected to selective logging, fire, and cyclone disturbance over 65 years, from 1952 to 2017. Irrespective of disturbance regimes, which varied between plots, rainforest trees recruited at much faster rates than the dominant wet‐sclerophyll forest trees, narrowly endemic species Syncarpia hillii and more common Lophostemon confertus. Syncarpia hillii did not recruit at the plot with the least disturbance and recruited only in low numbers at plots with more prominent disturbance regimes in the ≥10 cm at breast height size. Lophostemon confertus recruited at all plots but in much lower numbers than rainforest trees. Only five L. confertus were detected in the smallest size class (<10 cm diameter) in the 2017 survey. Overall, we find evidence that more pronounced disturbance regimes than those that have occurred over the past 65 years may be required to conserve this wet‐sclerophyll forest, as without intervention, transition to rainforest is a likely trajectory. Fire and other management tools should therefore be explored, in collaboration with Indigenous landowners, to ensure conservation of this wet‐sclerophyll forest.

Common garden comparisons confirm inherited differences in sensitivity to climate change between forest tree species.

The natural distribution, habitat, growth and evolutionary history of tree species are strongly dependent on ecological and genetic processes in ecosystems subject to fluctuating climatic conditions, but there have been few experimental comparisons of sensitivity between species. We compared the responses of two broadleaved tree species (Fagus sylvatica and Quercus petraea) and two conifer tree species (Pinus sylvestris and Picea abies) to climatic transfers by fitting models containing the same climatic variables. We used published data from European provenance test networks to model the responses of individual populations nested within species. A mixed model approach was applied to develop a response function for tree height over climatic transfer distance, taking into account the climatic conditions at both the seed source and the test location. The two broadleaved species had flat climatic response curves, indicating high levels of plasticity in populations, facilitating adaptation to a broader range of environments, and conferring a high potential for resilience in the face of climatic change. By contrast, the two conifer species had response curves with more pronounced slopes, indicating a lower resilience to climate change. This finding may reflect stronger genetic clines in P. sylvestris and P. abies, which constrain their climate responses to narrower climatic ranges. The response functions had maxima that deviated from the expected maximum productivity in the climate of provenance towards cooler/moister climate conditions, which we interpreted as an adaptation lag. Unilateral, linear regression analyses following transfer to warmer and drier sites confirmed a decline in productivity, predictive of the likely impact of ongoing climate change on forest populations. The responses to mimicked climate change evaluated here are of considerable interest for forestry and ecology, supporting projections of expected performance based on “real-time” field data.

Relationship between Space-Based Vegetation Productivity Index and Radial Growth of Main Tree Species in the Dry Afromontane Forest Remnants of Northern Ethiopia

Investigating the relations between Normalized Difference Vegetation Index (NDVI) and tree growth is vital for quantifying ecosystem primary productivity over large spatial and long temporal scales. In this study, the relationships between forest growth (tree-ring width indices) and space-based measurement of vegetation activity (NDVI) were examined in the dry Afromontane forest remnants of northern Ethiopia. The results showed that radial growth of the main tree species (Juniperus procera, Olea europaea and Podocarpus falcatus) is positively correlated with inter-annual NDVI values. Moreover, the relationships between ring width – rainfall and rainfall – NDVI were positive and significant (p&lt;0.05), suggesting that rainfall seasonality is an overriding growth-limiting factor in the study region. Rainfall during the wet-season largely controls cambial activities and phenological processes of the founding tree species, and hence affects overall vegetation dynamics in the region. Overall, the study showed the coupling of tree-ring growth and NDVI values with potential implications for understanding forest growth dynamics. Thus, it gives insights to the applicability of NDVI – treerings integration approach to predict landscape-level patterns of vegetation productivityKeywords: Dry Afromontane Forest, Remote-sensing, Tree-rings

Weed interference factors that affect the growth of an atlantic forest tree species

Weed interference factors that affect the growth of an atlantic forest tree species

Growth of Tree Species in Coexistence with Palisade Grass Urochloa brizantha (Hochst. ex A. Rich.) Stapf CV. Marandu

ABSTRACT: The effect of palisade grass (Urochloa brizantha) was evaluated on the growth of five tree species from the Atlantic Forest biome in Seropédica, RJ, Brasil. This study consisted of five experiments in a completely randomized design. The effect of grass on the growth of Cedrela fissilis, Guazuma ulmifolia, Schinus terebinthifolius, Sapindus saponaria, and Hymenaea courbaril was tested in pots at each experiment. Height, collar diameter, and plant mortality were measured monthly. Shoot and root dry matter of tree species and grass were evaluated at 180 days. A strong interference of palisade grass was observed on the growth of the five studied species. The reduction of growth in height and collar diameter reached 32 and 29% in S. saponaria and 26 and 44% in G. ulmifolia, respectively. Grass interference was even higher on dry matter accumulation, promoting reductions in the shoot that ranged from 48% in H. courbaril to 90% in G. ulmifolia and S. terebinthifolius. Root dry matter of tree species was reduced between 28 and 84% in relation to the control without the presence of grass. The species C. fissilis had a mortality rate of 83% in coexistence with U. brizantha. The other species, except S. saponaria, presented mortality from 15 to 30% under competition. This study evidences the importance of controlling grasses in reforestation projects aiming higher gains in growth and survival of tree species.

Diametric Growth of Tree Species in the Atlantic Forest, Paraná, Brazil.

Management of remnants in Atlantic Forest is an alternative for their conservation, however, information on the growth and ecology of those species is lacking. This study aimed to describe diametric growth of Balfourodendron riedelianum, Cordia trichotoma and Ocotea diospyrifolia based on its growth rings and to verify the relationship between this growth with the environmental characteristics in different altitude levels and forest types. Diametric growth was higher for the largest tree diameters of the three species. Based on the fitted growth model, the age in which mean annual increment in diameter becomes greater than the current annual increment was 55 years for B. riedelianum (DBH = 18.27 cm), 45 years for C. trichotoma (DBH = 26.56 cm) and 44 years for O. diospyrifolia (DBH = 26.05 cm). Environmental conditions and forest types affected diametric growth of these species. B. riedelianum and O. diospyrifolia showed higher diametric growth in plain regions with higher fertility soil and few frosts. C. trichotoma was negatively affected by low water availability in winter at lower altitudes and showed higher diametric growth at higher altitudes, where soil fertility is low but there is well-drainage, high rainfall and high relative humidity during the dry season.

Dendrochronology and climate in the Brazilian Atlantic Forest: Which species, where and how

As dendrochronology noticeably increased in tropical regions during the last three decades, some general patterns could emerge from comprehensive analyses of case studies. Here, we investigated the state of dendrochronology’s contributions to the bioclimatology of wood species in the Brazilian Atlantic Forest (AF). We asked: Which species and sites had cross-datable growth-ring series suitable for bioclimatic inference? What were the sampling and analytical methods applied? What do these studies tell us about plant-growth sensitivity to climate conditions? Which knowledge gaps may be identified? For this, we searched for articles addressing climate-growth relationships by means of cross-dated growth-ring chronologies within the AF. We found 11 articles, covering 16 chronologies from 10 species. The average number of trees in chronologies was 16 individuals. 87% of chronologies suggested a positive precipitation signal, and some positive temperature signal was identified in all chronologies that were compared to monthly or seasonal temperature series. The findings are supported by the specialized literature, which points out the influence of precipitation in the tropics. However, making stronger conclusions about the role of climate on the growth of AF tree species will require greater efforts in surveying the diverse tree flora and developing rigorous cross-dated chronologies. Keywords: climate-growth relationship, dendrochronological parameters, tropical forest, subtropical forest.

A whole-plant functional scheme predicting the early growth of tropical tree species: evidence from 15 tree species in Central Africa

This study highlighted the consistency of a functional scheme integrating leaf, stem and root traits, biomass allocation and stem anatomy for 15 tropical tree species at the seedling stage. This functional scheme was shaped by the trade-offs for resource use and the hydraulics of the plants and was found to determine seedling growth. Functional traits determine plant functioning, performance and response to the environment and define species functional strategy. The functional strategy of 15 African tree species was assessed by (1) highlighting the structure of traits covariance and the underlying functional trade-offs, (2) inferring a whole-plant functional scheme and (3) testing the correlation of the functional scheme with plant performance for two early developmental stages (seedlings and saplings). We selected 10 seedlings for each of the 15 species studied from a nursery in south-eastern Cameroon and measured 18 functional traits, including leaf, stem and root traits, biomass allocation and stem anatomy. We assessed the height and diameter growth of the seedlings and the DBH growth and survival for the saplings of nearby plantations. Multivariate analyses highlighted the covariations among the functional traits of the leaf/stem/root, biomass allocation ratios and stem anatomy. The major trait covariation axes were driven by two trade-offs, first between resource acquisition and conservation and second between hydraulic safety and efficiency. The axes were integrated into a Bayesian network inferring a functional scheme at the whole-plant scale, which was found to predict the growth of the seedlings but not the performance of the saplings. The functional strategies of the seedlings were determined by an integrated whole-plant scheme reflecting the trade-offs for resource use and plant hydraulics. The scheme predicted the growth of the seedlings through mechanistic pathways from the wood stem to all the plant traits, but it appeared to shift at the stage of the saplings.

Growth evaluation of native tree species planted on post coal mining reclamation site in East Kalimantan, Indonesia

Lestari DA, Fiqa AP, Fauziah, Budiharta S. 2019. Growth evaluation of native tree species planted on post coal mining reclamation site in East Kalimantan, Indonesia. Biodiversitas 20: 134-143. Mining activities affect environmental qualities including the loss of vegetation cover and the damages of physical, chemical and biological properties of soil. As such, regulations enacted by the Indonesian Government state a legal obligation for mining companies to carry out reclamation on post coal mining site. Reclamation is an activity carried out to organize, restore and improve of environmental quality after mining operations to enhance the highly disturbed ecosystem of mined land into ecologically usable state. Yet, there is little body of knowledge on how to monitor the effectiveness of reclamation in improving environmental quality of ex-mining land. Aims of this study are to evaluate of the growth of native tree species planted on various types of reclamation sites in a mining concession in East Kalimantan, and to analyze the most influencing factor of their growth. Growth parameters measured in this research were plant height, stem diameter and branch-free stem height of the planted species. Micro-climatic factors and diversity of understorey plants were also measured as environmental parameters. PCA (Principal Component Analysis) analysis was conducted using PAST 4.0. statistical program. The results shows that reclamation area of post coal mining in the study site which is most suitable for local plant species, especially Shorea balangeran, has a sloping terrain. PCA shows that factor having maximum influence on growth of planted species on the reclamation site is pH of soil. The higher is the soil pH (i.e. less acid), the better is the species growth because the soil conditions in the post-coal mining area tend to be acidic. This research suggests that in post coal mining reclamation using native trees two key factors to enhance growth performance of planted species are sloping terrain so as water is not inundated and soil pH so as it is not too acid.

Influence of Climate Variation on Growth of Tropical Tree Species in Western Kenya

Aims: Growth-climate relationships were examined in 7 tropical tree species growing in the Yala river basin of western Kenya: Acacia mearnsii, Cupressus lusitanica, Eucalyptus camaldulensis, Eucalyptus grandis, Eucalytus saligna, Mangifera indica, and Markhamia lutea.&#x0D; Methodology: Standardized basal area increments were correlated with monthly and seasonal (3 month periods) climate variables (precipitation, mean temperature, Climate Moisture Index) obtained from nearby meteorological stations.&#x0D; Results: A majority of the tree species (M. indica, C. lusitanica, E. camaldulensis, and E. saligna) showed positive correlations with monthly and seasonal precipitation and moisture index during periods of the long and short rainy seasons. This study also revealed significant correlations between monthly and seasonal temperature data and radial growth of M. indica, M. lutea and E. grandis. Growth of M. lutea was negatively affected by cool growing season conditions while M. indica and E. grandis experienced high temperature stress. &#x0D; Conclusion: Associations between radial growth of tropical tree species and temperature are generally rare in warm tropical regions, and for some of the species examined in this study that are non-native (i.e., M. indica and E. grandis), strongly suggests that they may be growing outside the optimal temperature conditions of their native geographical range.

Environmental drivers interactively affect individual tree growth across temperate European forests.

Forecasting the growth of tree species to future environmental changes requires a better understanding of its determinants. Tree growth is known to respond to global-change drivers such as climate change or atmospheric deposition, as well as to local land-use drivers such as forest management. Yet, large geographical scale studies examining interactive growth responses to multiple global-change drivers are relatively scarce and rarely consider management effects. Here, we assessed the interactive effects of three global-change drivers (temperature, precipitation and nitrogen deposition) on individual tree growth of three study species (Quercus robur/petraea, Fagus sylvatica and Fraxinus excelsior). We sampled trees along spatial environmental gradients across Europe and accounted for the effects of management for Quercus. We collected increment cores from 267 trees distributed over 151 plots in 19 forest regions and characterized their neighbouring environment to take into account potentially confounding factors such as tree size, competition, soil conditions and elevation. We demonstrate that growth responds interactively to global-change drivers, with species-specific sensitivities to the combined factors. Simultaneously high levels of precipitation and deposition benefited Fraxinus, but negatively affected Quercus' growth, highlighting species-specific interactive tree growth responses to combined drivers. For Fagus, a stronger growth response to higher temperatures was found when precipitation was also higher, illustrating the potential negative effects of drought stress under warming for this species. Furthermore, we show that past forest management can modulate the effects of changing temperatures on Quercus' growth; individuals in plots with a coppicing history showed stronger growth responses to higher temperatures. Overall, our findings highlight how tree growth can be interactively determined by global-change drivers, and how these growth responses might be modulated by past forest management. By showing future growth changes for scenarios of environmental change, we stress the importance of considering multiple drivers, including past management and their interactions, when predicting tree growth.

Seedling growth of savanna tree species from three continents under grass competition and nutrient limitation in a greenhouse experiment

Abstract Changes in savanna tree species composition, both within landscapes and across climatic gradients, suggest that species differ in their ability to utilize resources and cope with grass competition. Linking trait variation among species to their relative performance under resource limitation and competition treatments could provide mechanistic understanding of species’ turnover across environmental gradients in savannas. We investigated how tree species differ in response to competition from grasses and nutrient supply, and whether these responses can be related to plant traits. As humid savannas are often associated with low fertility, species of humid savannas may grow more efficiently under nutrient suppression than species from semi‐arid savannas. In heterogeneous grass swards, fast‐growing, resource‐wasteful species may be found in low grass biomass patches and slow‐growing, conservative species in high biomass patches. We compared seedlings of 40 tree species sampled from humid and semi‐arid savannas of three continents (Africa, Australia, South America) with and without grass competition and with high and low nutrient supply. We measured traits related to soil resource capture, light capture, and growth, and tested whether these traits were related to performance under the four treatments. All tree species were suppressed by grass competition and most by nutrient limitation. Only species from humid savannas in Australia grew better under nutrient limitation than their semi‐arid counterparts. Deciduous species from semi‐arid climates were more negatively impacted by grass competition than deciduous species from humid climates whereas the reverse pattern was observed among evergreen species. Faster growing species were more severely suppressed by grass competition and low nutrients than slower growing species. Traits associated with soil resource capture and seed mass supported growth under grass competition and nutrient limitation, but the traits differed by continent and by leaf habit. Synthesis. We found limited evidence that tree seedlings from humid savannas grow better under nutrient limitation than species of semi‐arid savannas. We confirmed that fast‐growing species may be advantaged in low grass biomass patches and conservative species in high biomass patches. Traits that improved performance under grass competition differed by continent, which may relate to differences in leaf habit and constraints on seed size.

Effectiveness and challenges of ecological engineering for desert riparian forest restoration along China’s largest inland river

Environmental flow, one of the main restoration measures for regulated rivers, aims to restore and sustain degraded riparian ecosystems and the human wellbeing that depends on these ecosystems with a reasonable magnitude, frequency, duration and timing of water flow. However, efficacies of environmental flows are often restrained by other demands along the river and inappropriate water management, leading to only spatially limited habitats being suitable for ecosystem functioning. This paper presents current restoration measures in the lower reaches of the Tarim riparian ecosystem in Northwest China and analyzes ecohydrological dynamics as a function of environmental flows. The groundwater level oscillation before/after and during the environmental flows (i.e., manmade water diversion) was examined, and the Mann-Kendall test was applied to identify the overall trend of change in groundwater depth from 2003 to 2011. The growth, distribution, health status (referred to as “vitality”) and renewal potentials of the dominant tree species Populus euphratica were quantified by using individual-based repeated measurements of P. euphratica morphology in two sampling sites (a 100-ha permanent plot and five random sampling plots with 50-m radii) at Arghan village in the lower reaches of the Tarim River. Based on these measurements, the effects of restoration measures on the groundwater recharge and the revitalization of degraded trees were assessed. The main contribution and achievements of the water diversion project on rehabilitation of the degraded riparian forests were evaluated; further, the limitations and challenges faced by of the restoration project were examined. The results of this research could help establish a reference for monitoring changes in riparian forests in Central Asia and possibly recommend restoration measures for riparian forest ecosystems in arid regions worldwide.

Linking climate, annual growth and competition in a Mediterranean forest: Pinus pinea in the Spanish Northern Plateau

Climate, competition and site conditions are the main drivers controlling annual secondary growth in tree species. These factors do no act independently on tree growth, but by means of interactions, resulting in mediated interactive effects. For example, the stress gradient hypothesis postulates alleviated interspecific competition under limiting spatial (site) or temporal (climate) resources. According to this, models predicting annual growth and yield for a given forest should consider these issues in their formulation. In this study, we present a modelling approach based on using data from permanent plots and dendrochronological analysis in order to describe annual tree growth in pure, even-aged stands of Pinus pinea L. in the Spanish Northern Plateau, a highly limiting environment due to its Mediterranean continental climate. Our method is based on identifying the different sources of variability by means of a multilevel linear mixed model, and thereby identifying the potential covariates explaining observed variability at the different spatiotemporal scales. Our results indicate that site related factors such as site index or dominant height exert a greater influence on annual secondary growth than size-symmetric competition. In addition, we found that the controlling influence of water stress is greater than that of temperatures on tree growth. Furthermore, our results allow evidence to be identified for the stress gradient hypothesis in temporal intraspecific interactions, since trees exposed to a higher degree of competition tend to grow more than expected in dry periods. In contrast, the effect of competition on growth, on average, tends to be aggravated at very poor sites. Finally, our modelling approach allows us to conduct growth and yield simulations under different climate scenarios at different spatial scales, providing results which point to significant decreases in timber and cone production under the more severe scenarios, which can be alleviated through more intensive silviculture.

Toward characterizing germination and early growth in the non-orthodox forest tree species Quercus ilex through complementary gel and gel-free proteomic analysis of embryo and seedlings

By using two complementary proteomics, gel-based and gel-free (shotgun) approaches, the protein profiles of the non-orthodox forest tree species Quercus ilex seeds during germination and early seedling growth have been compared. Proteins were extracted from embryo axis, radicle and shoot tissues at different developmental stages. Proteins were subjected to one- and two-dimensional gel electrophoresis. A multivariate analysis (PCA) revealed that SDS-PAGE clearly separated germination (0–24 h post-imbibition), postgermination (72–216 h post-imbibition) and early seedling growth stages (2 weeks post-imbibition). Image analysis of the two-dimensional gels revealed a total of 732 spots, 103 of which were significantly variable among developmental stages. After MALDI-TOF/TOF MS analysis, 90 spots were identified, belonging to six main functional categories: carbohydrate, amino acids, energy, and protein metabolism, biosynthesis of secondary metabolites, and redox processes. The gel-based approach disclosed important metabolic changes that occurred in the holm oak seed after the germination. However, few proteins were significantly altered during the germination period (from 0 h to 24 h post imbibition) and, because of that, a further shotgun analysis was therefore used to analyse changes in the protein profile during seed germination. Up to 1250 proteins could be confidently identified, with 153 being variable. They belonged to the main functional categories of carbohydrate, amino acids and secondary metabolism, protein degradation, and responses to abiotic stress. The accumulation of proteases and amino acids metabolism proteins in mature seeds can be reflecting the production of energy from the mobilization of storage proteins to start germination. These results, therefore, corroborate the hypothesis that the mature non-orthodox seeds of Q. ilex have all the machinery necessary for rapidly resuming metabolic activities and starting the germination process, in contrast to that occurs in orthodox seeds, which metabolic activity ceases in mature dry seeds.The use of a genus-specific database combined with the public Viridiplantae database improved the quality and quantity of protein identification in this orphan species. In addition, both proteomics approaches (gel-based and shotgun) were complementary, with shotgun increasing by over two-fold the coverage of the proteome analysed. Both approaches provided similar results and supported the same conclusions on the metabolic switch experienced by the seed upon germination. SignificanceThe optimal seed germination is a prerequisite for successful seedling establishment and plant vigour, being of great relevance in the case of crops and commercial woody plants. By using a complementary gel-based and gel-free proteomic strategy we have study the protein profiles of the non-orthodox forest tree species Quercus ilex seeds during germination and early seedling growth. The contribution of this work is of great importance, due to the complemented proteomic approaches giving similar clues to the metabolic state of the mature Q. ilex seed before the germination starts, and the metabolic switch experienced by the imbibed acorn until the seedling is established.

Radial Growth and Wood Density Reflect the Impacts and Susceptibility to Defoliation by Gypsy Moth and Climate in Radiata Pine.

Drought stress causes a reduction in tree growth and forest productivity, which could be aggravated by climate warming and defoliation due to moth outbreaks. We investigate how European gypsy moth (Lymantria dispar dispar L., Lepidoptera: Erebidae) outbreak and related climate conditions affected growth and wood features in host and non-host tree species in north-western Spain. There, radiata pine (Pinus radiata D. Don) plantations and chestnut (Castanea sativa Mill.) stands were defoliated by the moth larvae, whereas Maritime pine (Pinus pinaster Ait.) was not defoliated. The gypsy moth outbreak peaked in 2012 and 2013, and it was preceded by very warm spring conditions in 2011 and a dry-warm 2011–2012 winter. Using dendrochronology we compared growth responses to climate and defoliation of host species (radiata pine, chestnut) with the non-host species (Maritime pine). We also analyzed wood density derived from X-ray densitometry in defoliated and non-defoliated trees of radiata pine. We aimed to: (i) disentangle the relative effects of defoliation and climate stress on radial growth, and (ii) characterize defoliated trees of radiata pine according to their wood features (ring-width, maximum and minimum density). Radial growth during the outbreak (2012–2013) decreased on average 74% in defoliated (>50% of leaf area removed) trees of radiata pine, 43% in defoliated trees of chestnut, and 4% in non-defoliated trees of Maritime pine. After applying a BACI (Before-After-Control-Impact) type analysis, we concluded that the difference in the pattern of radial growth before and during the defoliation event was more likely due to the differences in climate between these two periods. Radiata pines produced abundant latewood intra-annual density fluctuations in 2006 and 2009 in response to wet summer conditions, suggesting a high climatic responsiveness. Minimum wood density was lower in defoliated than in non-defoliated trees of radiata pine prior to the outbreak, but increased during the outbreak. The pre-outbreak difference in minimum wood density suggests that the trees most affected by the outbreak produced tracheids with wider lumen and were more susceptible to drought stress. Results of this study illustrate (i) that the pattern of radial growth alone may be not a good indicator for reconstructing past defoliation events and (ii) that wood variables are reliable indicators for assessing the susceptibility of radiata pine to defoliation by the gypsy moth.

Manual Crowning Versus Cardboard in Forest Restoration: Costs and Effect on Seedling Development

ABSTRACT: Invasive grasses are one of the biggest obstacles to be overcome in restoration plantations. Thus, developing efficient and low-cost techniques to overcome this obstacle is a challenge for science and the ecological restoration practice. The objective of this study was to evaluate the effect of the use of cardboard for the crowning operation on the growth of forest tree species from the Atlantic Forest biome and on the operating costs of this technique in a reforestation implemented in Seropédica, Rio de Janeiro state. The predominant vegetation of the area was of Andropogon bicornis L. An experiment was installed in randomized blocks, with two treatments and 12 replications. The treatments consisted of crowning with cardboard and crowning with hoe. The used cardboard (50 x 50 cm) were pre-treated with a preservative solution with CuSO4. Treatments were applied to 11 forest species from the Atlantic Forest biome: Anadenanthera colubrina var. cebil (Griseb.) Altschul, Citharexylum myrianthum Cham., Enterolobium contortisiliquum (Vell.) Morong, Eugenia brasiliensis Lam, Eugenia uniflora Lam, Handroanthus chrysotrichus (Mart. ex DC.) Mattos, Hymenaea courbaril L., Inga laurina (Sw.) Willd., Plinia cauliflora (Mart.) Kausel, Plathymenia reticulata Benth. e Triplaris americana L. Evaluations were carried out as for height, diameter at collar height (DCH) and survival rate, 6, 12 and 18 months after planting. The costs of each crowning method were also quantified. Overall, the height, DCH and growth rates did not differ between the crowning treatments for the species evaluated. However, the cardboard crowning treatment showed a higher survival rate (80%) of plants, compared with the hoe crowning (73%). The cost of the crowning with cardboard over a 12-month period was 40% lower than that of the crowning with hoe. These results show that the cardboard crowning technique can be a viable and a cost effective alternative to replace the crowning with hoe in reforestation areas with species from the Atlantic Forest biome.