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José Luiz Stape - One of the best experts on this subject based on the ideXlab platform.
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variation in canopy structure leaf area light interception and light use efficiency among eucalyptus clones
Forest Ecology and Management, 2020Co-Authors: Eduardo Moré Mattos, Dan Binkley, Otavio Camargo Campoe, Clayton Alcarde Alvares, José Luiz StapeAbstract:Abstract Differences in growth rates between Eucalyptus clones depend on differences in the acquisition of resources, and the efficiency of using resources to produce carbohydrates and grow wood. We examined differences in canopy structure, light interception, and light use efficiency for the 18 TECHS clones in a common garden experiment in Brazil. The degree of clumping within canopies varied substantially among clones, leading to large differences in both leaf area and light interception per unit of leaf area. Two methods of determining plot-level leaf area index (LP-80 and LAI-2000) were moderately well correlated ( R 2 = 0.4), but both methods underestimated actual leaf area index (determined by destructive sampling) by about one-third. Completely overcast sky conditions increased accuracy of leaf area estimates, reducing variation among measurements within plots and lowering the number of samples needed to obtain a given level of precision. Genotypes with high leaf area clumping also had higher leaf angle inclinations than genotypes with lower clumping. The apparent light interception coefficient ( k ) averaged 0.56 for the LP-80, and 0.47 for the LAI-2000. The range of k estimates differed by up to 2-fold among clones, underscoring the limited generality of light extinction coefficients. Light interception ranged from about 70 to 95% of incoming light, and leaf area index accounted for only 30% of the pattern in light interception among clones. Differences in Stemwood production were influenced more strongly by clonal differences in efficiency of light use (Stemwood production per unit of light intercepted) than by differences in leaf area or light interception. The efficiency of producing wood per unit of light intercepted spanned a two-fold range, with higher efficiencies for more productive clones. We suggest that production ecology studies focus more on measurements of light interception than on leaf area, avoiding issues about difficult-to-measure features of crown and canopy structures. The additional step of characterizing light use efficiency would also be very important.
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the interactions of climate spacing and genetics on clonal eucalyptus plantations across brazil and uruguay
Forest Ecology and Management, 2017Co-Authors: Dan Binkley, Otavio Camargo Campoe, Clayton Alcarde Alvares, José Luiz Stape, Rafaela Lorenzato Carneiro, Italo Ramos CegattaAbstract:Abstract Intensively managed plantations account for 1.5% of the world’s forests, but they meet one-third of the demand for wood products. Eucalyptus plantations are among the most productive, with rates of growth depending heavily on genetics, silviculture, and climate. The TECHS Project examines productivity at 36 locations across a 3500 km gradient from Brazil to Uruguay, testing the interacting influences of genetics, temperature and precipitation on Stemwood production. Across all sites and genotypes, Stemwood production in the middle of the 6-year rotation (the peak period of growth) averaged 22 Mg ha−1 yr−1. Production varied by fivefold across sites, and by about 2-fold among genotypes within each site. The best clones at each location grew 1.5–4 Mg ha−1 yr−1 more than the average for all clones, underscoring the importance of matching genotypes to local site conditions. Contrary to patterns for natural forests across geographic gradients, Eucalyptus production declined with increasing temperature, dropping by 2.5 Mg ha−1 yr−1 for a 1 °C temperature increase. The temperature effect was likely driven in part by the geographic covariance of temperature and rainfall, as rainfall tended to decline by 78 mm yr−1 for each 1 °C increase in temperature. Stemwood production increased an average of 1.5 Mg ha−1 yr−1 for each 100 mm yr−1 increase in precipitation, but when the covariation of temperature and precipitation were included the apparent influence of precipitation declined to 0.4 Mg ha−1 yr−1 for each 100 mm yr−1 increase in precipitation. Future results will determine if within-site reductions in ambient rainfall have the same apparent influences as the rainfall pattern across the geographic gradient, as well as quantifying the importance of insects and pests in affecting growth. The supply of wood from intensively managed plantations will be strongly influenced by both temperature and precipitation at plantation locations, and with changing climates.
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soil carbon stocks and forest biomass following conversion of pasture to broadleaf and conifer plantations in southeastern brazil
Forest Ecology and Management, 2014Co-Authors: Rachel L Cook, Dan Binkley, José Luiz Stape, Joao Carlos T MendesAbstract:Abstract Increased soil carbon sequestration can potentially mitigate CO2 emission and can indicate sustainable forest management. This study aims to determine the relative influence of commercial plantation tree species on soil carbon following establishment on former tropical pastures. Soil carbon (organic horizon plus mineral soil from 0 to 45 cm) and Stemwood productivity were quantified from 6 to 34 year-old conifer and broadleaf plantations in a sandy Oxisol (Typic Hapludox) in southeastern Brazil. Study plots consisted of ten pastures paired with broadleaf plantations and ten additional broadleaf plantations paired with conifer plantations. Pastures primarily consisted of Brachiaria decumbens Stapf., while broadleaf plantations were primarily Eucalyptus, but also included one plot each of three other broadleaf species. Conifer stands were made up of Pinus species. Average Stemwood productivity (± standard error) was 9.7 (±1.0) Mg C ha−1 yr−1 for broadleaf and 5.7 (±0.5) Mg C ha−1 yr−1 for conifer plantations, but did not correlate to soil C. The soil C in the paired Pasture–Broadleaf plots averaged 36.0 ± 1.7 Mg C ha−1 in pastures and 36.8 ± 1.9 Mg C ha−1 in broadleaf plantations. The Broadleaf–Conifer plots averaged 38.3 ± 1.9 Mg C ha−1 for broadleaf plantations and 36.0 ± 1.6 Mg C ha−1 for conifers. Our results show little difference in soil C across vegetation types, providing evidence that conifer and broadleaf plantations overall maintain similar levels of soil carbon to pasture land-use up to 34 years following land conversion. Soil C differences between Pasture–Broadleaf pairs indicated a small decline in soil C accretion early after plantation establishment, followed by recovery to slightly higher accretion rates.
Bjarne Holmbom - One of the best experts on this subject based on the ideXlab platform.
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lipophilic extractives in populus euramericana guariento Stemwood and bark
Journal of Wood Chemistry and Technology, 2010Co-Authors: Menghua Qin, Jarl Hemming, Bjarne Holmbom, Na Liu, Stefan WillförAbstract:Abstract The lipophilic extractives in Stemwood and bark from three different heights of Populus × euramericana “Guariento” were analyzed. The bark samples, especially from 4 and 8 meters height, contained much more extractives than the Stemwood samples. The lipophilic extractives identified by Gas Chromatography–Mass Spectroscopy (GC-MS) were composed of five component groups (i.e. triglycerides, steryl esters, free fatty acids, sterols, and free fatty alcohols both in the Stemwood and bark). Besides ferulic acid esters, α-amyrin and its esters, 4-hydroxycinnamic acid esters of fatty alcohols were also identified in the Stemwood and bark. Small amounts of alkanes and oligomeric or polymeric material with higher molar mass than triglycerides were present only in the bark. Glycerides, mainly triglycerides, were the largest component group of the lipophilic extractives. The high proportion of short-chain fatty acids released after alkaline hydrolysis are beneficial when removing pitch particles or fatty aci...
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Antioxidant flavonoids from knotwood of Jack pine and European aspen
European Journal of Wood and Wood Products, 2006Co-Authors: Madalina Neacsu, Suvi Pietarinen, Rainer Sjöholm, Patrik Eklund, Markku Ahotupa, Bjarne Holmbom, Stefan WillförAbstract:Flavonoids have recently been found in large amounts in knotwood and Stemwood of several tree species. Six flavonoids, two flavonoid glucosides, and one cinnamic acid derivative were isolated from Jack pine and European aspen knotwood and structurally characterised using GC-MS, HR-MS, and NMR spectroscopic analyses. Isolated compounds were further assessed on basis of their potency to inhibit lipid peroxidation and scavenge peroxyl radicals. All tested compounds possessed antioxidant properties close to that of the reference compound Trolox.
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characterisation of volatile organic compounds in Stemwood using solid phase microextraction
Phytochemical Analysis, 2006Co-Authors: A Wajs, Stefan Willför, Markku Reunanen, Andrey Pranovich, Bjarne HolmbomAbstract:Solid-phase microextraction (SPME), hydrodistillation and dynamic headspace combined with GC and GC-MS were applied and compared for the analysis of volatile organic compounds (VOCs) from coniferous wood. The SPME conditions (type of fibre, size of wood sample, temperature and exposure time) were optimised, and more than 100 VOCs and semi-volatile compounds extracted and identified from the sapwood and heartwood of Norway spruce (Picea abies). The total number of mono- and sesquiterpenes eluted and identified was similar for the SPME and hydrodistillation methods, but more semi-volatile compounds were released by hydrodistillation. By applying dynamic headspace at room temperature, it was possible to analyse only the most volatile compounds. The qualitative composition of VOCs was similar in spruce sapwood and heartwood, although Z-beta-ocimene occurred only in sapwood while fenchol was present only in heartwood. SPME sampling coupled with GC, applied here to the analysis of VOCs released from Stemwood of firs for the first time, is a convenient, sensitive, fast, solvent-free and simple method for the determination of wood volatiles. The technique requires much smaller sample amounts compared with hydrodistillation, and the total amount of VOCs extracted and identified is higher than that obtained by hydrodistillation or dynamic headspace. The relative ratios of the main mono- and sesquiterpenes and -terpenoids were similar using the SPME-GC and hydrodistillation methods.
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distribution of lignans in knots and adjacent Stemwood of picea abies
European Journal of Wood and Wood Products, 2005Co-Authors: Stefan Willför, Bjarne Holmbom, Anna Sundberg, Patrik Rehn, Pekka SaranpääAbstract:The distribution of lignans in knots, i.e., the branch bases encased in the Stemwood, and in the adjacent Stemwood of Norway spruce (Picea abies) was studied. Hydrophilic extracts in samples of three annual rings from the side wood of knots, as well as samples from the surrounding Stemwood, were analysed by GC and GC-MS. The knots had an exceptionally high content of lignans (up to 15% w/w), compared to the Stemwood (less than 0.05% w/w). The content decreased clearly in the radial direction from the knot pith towards the outerwood, to come down to the same level as in the surrounding Stemwood. In the branches, the lignan content also decreased in the radial direction from the branch pith outwards. The lignan content decreased sharply outwards in the branches and came down to the same levels as in the Stemwood already 20 cm outside of the stem.
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bioactive phenolic substances in industrially important tree species part 2 knots and Stemwood of fir species
Holzforschung, 2004Co-Authors: Stefan Willför, Markku Reunanen, Jarl Hemming, Linda Nisula, Bjarne HolmbomAbstract:Knots, i.e. branch bases inside tree stems, in fir trees contained remarkably higher concentrations of lignans, oligolignans, and juvabiones than the adjacent Stemwood. Eight fir species were analysed (Abies sibirica, A. lasiocarpa, A. balsamea, A. alba, A. amabilis, A. veitchii, A. sachalinensis, and A. concolor). The amount of lignans could in some knots exceeds 6% (w/w) and the knots generally contained 20-50 times more lignans than the Stemwood. However, there were large variations, not only between species but also even between knots in the same tree. Secoisolariciresinol was the predominant lignan in all knots. The lignans occur in free form in the knots and are easily extracted with polar solvents. In addition to the lignans, oligomeric aromatic substances, mainly sesquineo- and dineolignans, and juvabiones were accumulated in the knotwood. Secoisolariciresinol, but also lariciresinol (Abies alba) and 7-hydroxymatairesinol (A. amabilis), could be extracted in large scale from fir knots at pulp and paper mills. The ready availability of large amounts of lignans and oligolignans now enables research to assess their bioactivity and provide the base for applications in medicine and nutrition, or as natural antioxidants and antimicrobial agents in various technical products.
Nick J Balster - One of the best experts on this subject based on the ideXlab platform.
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coupling tree ring δ13c and δ15n to test the effect of fertilization on mature douglas fir pseudotsuga menziesii var glauca stands across the interior northwest usa
Tree Physiology, 2009Co-Authors: Nick J Balster, John D Marshall, Murray K ClaytonAbstract:Nitrogen (N) fertilization causes long-term increases in biomass production in many N-limited forests around the world, but the mechanistic basis underlying the increase is often unclear. One possibility, especially in summer-dry climates, is that N fertilization increases the efficiency with which a finite water supply is consumed to support photosynthesis. This increase is achieved by a reduction in the canopy-integrated concentration of internal CO(2) and thus discrimination against (13)C. We used stable isotopes of carbon (delta(13)C) in tree rings to experimentally test the physiological impact of N fertilization on mature Douglas-fir (Pseudotsuga menziesii Franco var. glauca) stands across the geographic extent of the Intermountain West, USA. The concentration and the stable isotopes of N (delta(15)N) in tree rings were also used to assess the presence and activity of fertilizer N. We hypothesized that N fertilization would (i) increase delta(15)N and N concentration of Stemwood relative to non-fertilized stands and (ii) increase Stemwood delta(13)C as photosynthetic gas exchange responded to the additional N. This experiment included two rates of urea addition, 178 kg ha(-1) (low) and 357 kg ha(-1) (high), which were applied twice over a 6-year interval bracketed by the 18 years of wood production measured in this study. Foliar N concentrations measured the year after each fertilization treatment suggest that the fertilizer N had been assimilated by the trees (P < 0.001). The N fertilization significantly enriched Stemwood delta(15)N by 1.3 per thousand at the low fertilization rate and by 2.4 per thousand at the high rate (P < 0.001) despite variation in soil N between sites. However, we found no significant effect of the N fertilizer on delta(13)C of the annual rings (P = 0.76). These data lead us to suggest that alternative mechanisms underlie the growth response to fertilizer, i.e., increase in canopy area and shifts in biomass allocation.
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eight year responses of light interception effective leaf area index and Stemwood production in fertilized stands of interior douglas fir pseudotsuga menziesii var glauca
Canadian Journal of Forest Research, 2000Co-Authors: Nick J Balster, John D MarshallAbstract:Data from 72 Douglas-fir (Pseudotsuga menziesii var. glauca (Beissn.) Franco) plots across the Interior Northwest were used to determine whether (i) increased intercepted photosynthetically active radiation (%IPAR), effective leaf area index (LAIe), and Stemwood volume production (cubic metres Stemwood per hectare per year) could still be detected 7 or 8 years after nitrogen fertilization and (ii) fertilization would increase the efficiency by which light is converted into Stemwood volume. Projected LAIe varied from 1.82 to 6.07 m2·m-2 on the control plots. The fertilized plots intercepted 9-11% more light than the control plots (P < 0.001); they also had 22-25% higher LAIe than the control plots (P < 0.001). Stemwood volume production increased by 25-29% relative to the control (P < 0.001) and increased exponentially with %IPAR across all study plots (R2 = 0.57). Stemwood growth efficiency averaged 12.0 ± 0.4 (mean ± SE), 13.5 ± 0.4, and 13.7 ± 0.4 m3·ha-1·a-1 per IPAR for the control, low fertilization,...
Ross E Mcmurtrie - One of the best experts on this subject based on the ideXlab platform.
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long term changes in productivity of eucalypt plantations under different harvest residue and nitrogen management practices a modelling analysis
Forest Ecology and Management, 2005Co-Authors: Marc Corbeels, Ross E Mcmurtrie, David A Pepper, D S Mendham, T S Grove, A M OconnellAbstract:Abstract Sustaining productivity in short-rotation forest plantations over multiple rotations can be problematic, when nutrient inputs to soil are small compared to exports off-site during harvest. For example, there are concerns about sustained productivity of Eucalyptus globulus plantations growing on ex-pasture land in south-western Australia because nitrogen (N) inputs from fertilisation and leguminous species are low. One way of improving the N balance of the plantation system is through retention of tree residues produced during harvest operations. We used the Generic Decomposition And Yield (G’DAY) model of Carbon (C) and N cycling in plant and soil to investigate the relationship between soil N fertility and stem productivity when E. globulus planted on legume-based pasture land is grown over twenty 8-year rotations under different scenarios of harvest residue and N management. The scenarios included Stemwood harvesting with retention of harvest residues, denoted “single slash” (SS), double the amount of harvest residues, denoted “double slash” (DS), no harvest residue (NS), burning of harvest residues and tree litter (B) and addition of fertiliser N equal to N removed in Stemwood harvest (F). We parameterised and tested G’DAY using data from a field experiment conducted at two second-rotation E. globulus plantation sites with contrasting productivity. Experimental treatments at these sites included SS, DS, NS and B. With the model we were able to accurately reproduce observed Stemwood growth of second-rotation stands for all treatments at both sites (r = 0.99). Model simulations overestimated soil N mineralisation at the more productive site (relative error, E, ranged from −14 to −24), and underestimated it at the less productive site (+5
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Analytical model of Stemwood growth in relation to nitrogen supply.
Tree physiology, 1996Co-Authors: Roderick C Dewar, Ross E McmurtrieAbstract:We derived a simplified version of a previously published process-based model of forest productivity and used it to gain information about the dependence of Stemwood growth on nitrogen supply. The simplifications we made led to the following general expression for Stemwood carbon (c(w)) as a function of stand age (t), which shows explicitly the main factors involved: c(w)(t) = eta(w)G*/ micro (w)(1 - lambdae(- micro (w)t) - micro (w)e(-lambdat)/lambda - micro (w)), where eta(w) is the fraction of total carbon production (G) allocated to Stemwood, G* is the equilibrium value of G at canopy closure, lambda describes the rate at which G approaches G*, and micro (w) is the combined specific rate of Stemwood maintenance respiration and senescence. According to this equation, which describes a sigmoidal growth curve, c(w) is zero initially and asymptotically approaches eta(w)G*/ micro (w) with the rate of approach dependent on lambda and micro (w). We used this result to derive corresponding expressions for the maximum mean annual stem-wood volume increment (Y) and optimal rotation length (T). By calculating the quantities G* and lambda (which characterize the variation of carbon production with stand age) as functions of the supply rate of plant-available nitrogen (U(o)), we estimated the responses of Y and T to changes in U(o). For a plausible set of parameter values, as U(o) increased from 50 to 150 kg N ha(-1) year(-1), Y increased approximately linearly from 8 to 25 m(3) ha(-1) year(-1) (mainly as a result of increasing G*), whereas T decreased from 21 to 18 years (due to increasing lambda). The sensitivity of Y and T to other model parameters was also investigated. The analytical model provides a useful basis for examining the effects of changes in climate and nutrient supply on sustainable forest productivity, and may also help in interpreting the behavior of more complex process-based models of forest growth.
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sustainable Stemwood yield in relation to the nitrogen balance of forest plantations a model analysis
Tree Physiology, 1996Co-Authors: Roderick C Dewar, Ross E McmurtrieAbstract:We used an existing analytical model of Stemwood growth in relation to nitrogen supply, which we describe in an accompanying paper, to examine the long-term effects of harvesting and fire on tree growth. Our analysis takes into account the balance between nitrogen additions from deposition, fixation, and fertilizer applications, and nitrogen losses from Stemwood harvesting, regeneration burning, leaching and gaseous emissions. Using a plausible set of parameter values for Eucalyptus, we conclude that nitrogen loss through fire is the main factor limiting sustainable yield, defined as the maximum mean annual Stemwood volume increment obtained in the steady state, if management practices are continued indefinitely. The sustainable yield is 30 m(3) ha(-1) year(-1) with harvesting only, 15 m(3) ha(-1) year(-1) with harvesting and regeneration burning, and 13 m(3) ha(-1) year(-1) with harvesting, fire, leaching and gaseous emissions combined. Our approach uses a simple graphical analysis that provides a useful framework for examining the factors affecting sustainable yield. The graphical analysis is also useful for extending the application of the present model to the effects of climate change on sustainable yield, or for interpreting the behavior of other models of sustainable forest growth.
Detlef P. Van Vuuren - One of the best experts on this subject based on the ideXlab platform.
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Modeling forest plantations for carbon uptake with the LPJmL dynamic global vegetation model
Earth System Dynamics, 2019Co-Authors: Maarten C. Braakhekke, Jonathan C. Doelman, Peter Baas, Christoph Müller, Sibyll Schaphoff, Elke Stehfest, Detlef P. Van VuurenAbstract:Abstract. We present an extension of the dynamic global vegetation model, Lund–Potsdam–Jena Managed Land (LPJmL), to simulate planted forests intended for carbon (C) sequestration. We implemented three functional types to simulate plantation trees in temperate, tropical, and boreal climates. The parameters of these functional types were optimized to fit target growth curves (TGCs). These curves represent the evolution of Stemwood C over time in typical productive plantations and were derived by combining field observations and LPJmL estimates for equivalent natural forests. While the calibrated model underestimates Stemwood C growth rates compared to the TGCs, it represents substantial improvement over using natural forests to represent afforestation. Based on a simulation experiment in which we compared global natural forest versus global forest plantation, we found that forest plantations allow for much larger C uptake rates on the timescale of 100 years, with a maximum difference of a factor of 1.9, around 54 years. In subsequent simulations for an ambitious but realistic scenario in which 650 Mha (14 % of global managed land, 4.5 % of global land surface) are converted to forest over 85 years, we found that natural forests take up 37 PgC versus 48 PgC for forest plantations. Comparing these results to estimations of C sequestration required to achieve the 2 ∘ C climate target, we conclude that afforestation can offer a substantial contribution to climate mitigation. Full evaluation of afforestation as a climate change mitigation strategy requires an integrated assessment which considers all relevant aspects, including costs, biodiversity, and trade-offs with other land-use types. Our extended version of LPJmL can contribute to such an assessment by providing improved estimates of C uptake rates by forest plantations.
