This study evaluated boron diff usion from raw boron minerals ulexite and colemanite with low water solubility in comparison to disodium octaborate tetrahydrate(DOT).Tests were conducted using sugi(Cryptomeria japonic...This study evaluated boron diff usion from raw boron minerals ulexite and colemanite with low water solubility in comparison to disodium octaborate tetrahydrate(DOT).Tests were conducted using sugi(Cryptomeria japonica(L.)f.D.Don)sapwood and heartwood blocks conditioned to 30,60,and 90%target moisture content.The blocks were fi lled with the boron compounds through treatment holes and diff usion was observed at three assay zones across the blocks after 7,30,60 or 90-day incubation period at room temperatures.For comparison,ethylene glycol was also introduced into the holes to elevate boron diff usion.As expected,diff usion increased with increased moisture content and levels were higher at the 60%and 90%moisture levels compared to the 30%level.With some exceptions,boron levels did not follow consistent gradients with distance away from the treatment hole.Incorporation of ethylene glycol helped increase boron levels,even in heartwood blocks.Boron levels were higher from the ulexite source than from colemanite;however,DOT treatments resulted in the highest boron diff usion rates as a result of greater water solubility compared to both raw boron minerals.The results suggest that ulexite together with ethylene glycol may be useful in both sapwood and heartwood materials when kept at high moisture levels for extended periods.展开更多
High-elevation,snow-dependent,semiarid ecosystems across southwestern United States are expected to be vulnerable to climate change,including drought and fi re,with implications for various aspects of the water cycle....High-elevation,snow-dependent,semiarid ecosystems across southwestern United States are expected to be vulnerable to climate change,including drought and fi re,with implications for various aspects of the water cycle.To that end,much less is known about the dynamics of transpiration,an important component of the water cycle across this region.At the individual-tree scale,transpiration is estimated by scaling mean sap fl ux density by the hydroactive sapwood area(SA).SA also remains a key factor in eff ectively scaling individual tree water-use to stand level.SA across large spatial scales is normally established by relating SA of a few trees to primary size measures,e.g.,diameter at breast height(DBH),tree height(H),or canopy diameter(CD).Considering the importance of SA in scaling transpiration,the primary objective of this study was therefore to establish six species-specifi c(aspen,maple,white fi r,ponderosa pine,Douglas fi r,Englemann spruce)allometric relationships between SA and three primary size measures(DBH,CD,or H)across two high-elevation,snow-dependent,semiarid ecosystems in New Mexico and Arizona.Based on multiple statistical criteria(coeffi cient of determination,index of agreement,Nash–Sutcliff e effi-ciency)and ease of measurement in the forest,we identifi ed DBH as the primary independent variable for estimating SA across all sites.Based on group regression analysis,we found allometric relationships to be signifi cantly(p<0.05)diff erent for the same species(ponderosa pine,Douglas-fi r)across diff erent sites.Overall,our allometric relationships provide a valuable database for estimating transpiration at diff erent spatial scales from sap fl ow data in some of our most vulnerable ecosystems.展开更多
We evaluated heartwood, sapwood and bark content in teak trees.A total of 27 sample plots were laid out in teak plantations raised by State Forest Department in Karnataka covering different age groups(11 36 years), de...We evaluated heartwood, sapwood and bark content in teak trees.A total of 27 sample plots were laid out in teak plantations raised by State Forest Department in Karnataka covering different age groups(11 36 years), density(516 2061 trees/ha) and sites.From these plantations, a total of 130 trees were felled for estimating the yield and bark content in relation to diameter at breast height(DBH), age and density.Bark content ranged from 22.2% 54.3%.Heartwood and sapwood content were analyzed by sampling five trees each from two different plantations, one 30 years old at 553 trees ha-1and the other 32 years old at 911trees ha-1.The highest heartwood proportion of stem wood volume(over-bark) was 56.3% and the lowest was 37.1%.The sapwood proportion ranged from 12.9% 23.0%, while the bark content ranged from27.8% 43.5%.The heartwood proportion increased with DBH, while the proportion of bark decreased.The sapwood proportion did not vary with DBH.The bark content decreased with increasing age, but increased with stand density.There was no significant difference in heartwood content with respect to age or stand density because the ages of the two stands were similar.A larger dataset from young to mature stands is needed to describe the relationships between age and stand density and heartwood,sapwood and bark content of trees.展开更多
Sapwood density and bark thickness of Calophyllum inophyllum L. (a multipurpose durable timber species) were studied in various locations in Northern Australia and in Sri Lanka. Measurements were taken non-destructive...Sapwood density and bark thickness of Calophyllum inophyllum L. (a multipurpose durable timber species) were studied in various locations in Northern Australia and in Sri Lanka. Measurements were taken non-destructively by using core sampling and bark gauge. From each provenance, 4-15 mature trees having girth at breast height over bark (GBHOB) at 100-150 cm were selected on the basis of the population size. Significant (p<0.05) hemispheric and provenance variations in bark thickness were found. Variations in the bark thickness are influenced by environmental variables. Variations in sapwood density were less pronounced compared to that of bark thickness. Variations in sapwood density are likely to be governed by genotypic variations.展开更多
A desorption isotherm is a very important basis in the understanding of drying process. In this study, the desorption isotherms from the sapwood of Mexican pine (Pinus pseudostrobus Lindl.) were determined by the grav...A desorption isotherm is a very important basis in the understanding of drying process. In this study, the desorption isotherms from the sapwood of Mexican pine (Pinus pseudostrobus Lindl.) were determined by the gravimetric method (discontinuous control of sample weight) at 30℃ and 50℃. The salt method was used in the range of water activities from 0.11 to 0.89. The results show that the desorption ability of Mexican pine sapwood increased with temperature at a given relative humidity. The experimental data was further simulated with the models, i.e., BET, GAB, Oswin and Henderson models. The GAB, Oswin and Henderson models allow the representation of the entire desorption isotherms. The BET model showed a better fit for water activity lower than 0.35, with a mean relative deviation of 0.0286 at 30℃ and 0.0167 at 50℃. Simultaneously, the BET model gave a better representation of moisture content in the monolayer saturation region. Overall, the GAB model ensured the best simulation of the entire isotherm, while the Henderson model displayed the worst simulation.展开更多
Aims Natural and anthropogenic changes in forests can have important influences on transpiration and water production.Understanding the effects of increasing disturbances,due for example to climate change and forest h...Aims Natural and anthropogenic changes in forests can have important influences on transpiration and water production.Understanding the effects of increasing disturbances,due for example to climate change and forest harvesting,requires detailed information on how forest density and structural attributes relate to transpiration.Mean annual transpiration of eucalypt forest communities is often strongly correlated with total cross-sectional sapwood area.Our aim was to test an efficient method for estimating sapwood area at_(1.3)m height(SA_(1.3))in a large number of trees to understand the spatial heterogeneity of tree and stand sapwood area within and between forest communities,and develop allometric relationships that predict SA_(1.3)with forest inventory data.We also apply tree competition models to determine the degree to which the relationship between SA_(1.3)and tree basal area at_(1.3)m height(BABA_(1.3))is influenced by competition.Methods We visited 25 recently harvested southeastern Australian forest sites consisting of 1379 trees and 5 Eucalyptus species to evaluate a new efficient data collection method for estimating SA_(1.3)with tree taper and stump dimensions data using mixed effects models.The locations of 784 stumps within one 5-ha site were accurately mapped using an unmanned aerial vehicle(UAV),and four distance-dependent tree competition models were applied across the site to explain within-stand variation in the ratio of SA_(1.3)to BABA_(1.3).Data from 24 additional sites,consisting of ten 15 m radial plots per site,were used to analyse within-site variation in R_(Ha)(the ratio of stand sapwood area SA_(Ha)to stand basal area BABA_(Ha)).The radial plots were merged within each site to evaluate between-site variations in R_(Ha)across the landscape.For predicting SA_(Ha)with forest inventory data,we computed the relationship between SA_(Ha)and a new index of total stem perimeter per hectare,defined as√BA_(Ha)N_(T),where N_(T)is tree stocking density.Important Findings Our 1379 measured stems represent the most comprehensive measure of sapwood area,surpassing the 757 measured stems in native eucalypt forests published in literature.The species-specific R_(Ha) varied considerably across sites and therefore extrapolating SA_(Ha)with spatially distributed BABA_(Ha)maps and a generalized R_(Ha) would introduce local uncertainty.We found that the species-specific stem perimeter index was more effective at capturing variability in SA_(Ha)across the landscape using forest composition,structure and density data(R^(2):0.72–0.77).The strong correlation between tree SA_(1.3)and BABA_(1.3)improved slightly using tree competition models(R^(2)increased from 0.86 to 0.88).Relating SA_(Ha)to routinely measured forest inventory attributes within permanent plots and Light Detection and Ranging(LiDAR)data may provide opportunities to map forest water use in time and space across large areas disturbed by wildfire and logging.展开更多
Measurement of the longitudinal gas permeability was made for air-dried sapwood specimens from Masson pine (Pinus massoniana). Results showed that air-dried Masson pine sapwood was one of the most permeable softwoods....Measurement of the longitudinal gas permeability was made for air-dried sapwood specimens from Masson pine (Pinus massoniana). Results showed that air-dried Masson pine sapwood was one of the most permeable softwoods. The investigated specimens had an average longitudinal gas permeability of 4.60 ×10-13 m3/m, and the permeability ranged from 1.06 ×10-13 to 1.12 ×10-12 m3/m. The Kruskal- Wallis Test indicated that, generally, there was no correlation between the longitudinal gas permeability and the trees from which specimens were prepared, and tree height had no significant effect on the longitudinalgas permeability.展开更多
为了解喀斯特地区树种适应水分亏缺生境的内在机制,选择广西弄岗喀斯特森林9种主要树种,分析树种间水力结构及相关性状的差异及相关性。结果显示:供试9种树种间的最大边材比导率、最大叶片比导率、胡伯尔值、木质部导管直径及木材密度...为了解喀斯特地区树种适应水分亏缺生境的内在机制,选择广西弄岗喀斯特森林9种主要树种,分析树种间水力结构及相关性状的差异及相关性。结果显示:供试9种树种间的最大边材比导率、最大叶片比导率、胡伯尔值、木质部导管直径及木材密度存在极显著(P<0.01)差异,其中,海南椴〔Diplodiscus trichospermus(Merrill)Y.Tang〕的最大边材比导率、最大叶片比导率以及木质部导管直径均最大,但胡伯尔值和木材密度最小。干季和湿季,供试9种树种间木质部导水率丧失百分比(PLC)均存在极显著差异,且金丝李(Garcinia paucinervis Chun et How)的PLC值均最高,分别为44.39%和38.92%。除闭花木〔Cleistanthus sumatranus(Miq.)Muell.Arg.〕、海南椴和淡黄金花茶(Camellia flavida Chang)外,其他6种树种PLC值在干季和湿季间无显著(P>0.05)差异,表明喀斯特地区树种耐干旱能力普遍较强。相关性分析结果表明:单叶叶面积与最大边材比导率、木质部导管直径和叶片净光合速率呈极显著(P<0.01)或显著(P<0.05)正相关,但与木材密度呈极显著负相关。综上所述,喀斯特地区木材密度较大的树种虽然耐旱性较强,但木质部水分运输效率会降低,进而使叶片净光合速率降低;反之,木材密度较小的树种虽然有利于木质部水分运输效率提高及碳固定,但是其耐旱性降低;水力结构功能特征间的关系既存在协同也存在一定的权衡。展开更多
基金The authors acknowledge Eti Maden Operations General Directorate,Ankara,Turkey for the boron minerals and DOT used in the study.
文摘This study evaluated boron diff usion from raw boron minerals ulexite and colemanite with low water solubility in comparison to disodium octaborate tetrahydrate(DOT).Tests were conducted using sugi(Cryptomeria japonica(L.)f.D.Don)sapwood and heartwood blocks conditioned to 30,60,and 90%target moisture content.The blocks were fi lled with the boron compounds through treatment holes and diff usion was observed at three assay zones across the blocks after 7,30,60 or 90-day incubation period at room temperatures.For comparison,ethylene glycol was also introduced into the holes to elevate boron diff usion.As expected,diff usion increased with increased moisture content and levels were higher at the 60%and 90%moisture levels compared to the 30%level.With some exceptions,boron levels did not follow consistent gradients with distance away from the treatment hole.Incorporation of ethylene glycol helped increase boron levels,even in heartwood blocks.Boron levels were higher from the ulexite source than from colemanite;however,DOT treatments resulted in the highest boron diff usion rates as a result of greater water solubility compared to both raw boron minerals.The results suggest that ulexite together with ethylene glycol may be useful in both sapwood and heartwood materials when kept at high moisture levels for extended periods.
基金A very special note of thanks to Dr.Valerie Trouet,Dr.David J.P.Moore,Emily Dynes,Ian Shiach,Dr.Julia N.Perdrial,Michael Pohlmann and Lori Lovell during the collection of tree core samples and the tree survey.M.R.A.was supported by the DOE Regional and Global Climate Modeling program DE-SC0016011 and by the University of Arizona Water,Environment,and Energy Solutions(WEES)and Sustainability of Semi-Arid Hydrology and Riparian Areas(SAHRA)programs.
文摘High-elevation,snow-dependent,semiarid ecosystems across southwestern United States are expected to be vulnerable to climate change,including drought and fi re,with implications for various aspects of the water cycle.To that end,much less is known about the dynamics of transpiration,an important component of the water cycle across this region.At the individual-tree scale,transpiration is estimated by scaling mean sap fl ux density by the hydroactive sapwood area(SA).SA also remains a key factor in eff ectively scaling individual tree water-use to stand level.SA across large spatial scales is normally established by relating SA of a few trees to primary size measures,e.g.,diameter at breast height(DBH),tree height(H),or canopy diameter(CD).Considering the importance of SA in scaling transpiration,the primary objective of this study was therefore to establish six species-specifi c(aspen,maple,white fi r,ponderosa pine,Douglas fi r,Englemann spruce)allometric relationships between SA and three primary size measures(DBH,CD,or H)across two high-elevation,snow-dependent,semiarid ecosystems in New Mexico and Arizona.Based on multiple statistical criteria(coeffi cient of determination,index of agreement,Nash–Sutcliff e effi-ciency)and ease of measurement in the forest,we identifi ed DBH as the primary independent variable for estimating SA across all sites.Based on group regression analysis,we found allometric relationships to be signifi cantly(p<0.05)diff erent for the same species(ponderosa pine,Douglas-fi r)across diff erent sites.Overall,our allometric relationships provide a valuable database for estimating transpiration at diff erent spatial scales from sap fl ow data in some of our most vulnerable ecosystems.
文摘We evaluated heartwood, sapwood and bark content in teak trees.A total of 27 sample plots were laid out in teak plantations raised by State Forest Department in Karnataka covering different age groups(11 36 years), density(516 2061 trees/ha) and sites.From these plantations, a total of 130 trees were felled for estimating the yield and bark content in relation to diameter at breast height(DBH), age and density.Bark content ranged from 22.2% 54.3%.Heartwood and sapwood content were analyzed by sampling five trees each from two different plantations, one 30 years old at 553 trees ha-1and the other 32 years old at 911trees ha-1.The highest heartwood proportion of stem wood volume(over-bark) was 56.3% and the lowest was 37.1%.The sapwood proportion ranged from 12.9% 23.0%, while the bark content ranged from27.8% 43.5%.The heartwood proportion increased with DBH, while the proportion of bark decreased.The sapwood proportion did not vary with DBH.The bark content decreased with increasing age, but increased with stand density.There was no significant difference in heartwood content with respect to age or stand density because the ages of the two stands were similar.A larger dataset from young to mature stands is needed to describe the relationships between age and stand density and heartwood,sapwood and bark content of trees.
文摘Sapwood density and bark thickness of Calophyllum inophyllum L. (a multipurpose durable timber species) were studied in various locations in Northern Australia and in Sri Lanka. Measurements were taken non-destructively by using core sampling and bark gauge. From each provenance, 4-15 mature trees having girth at breast height over bark (GBHOB) at 100-150 cm were selected on the basis of the population size. Significant (p<0.05) hemispheric and provenance variations in bark thickness were found. Variations in the bark thickness are influenced by environmental variables. Variations in sapwood density were less pronounced compared to that of bark thickness. Variations in sapwood density are likely to be governed by genotypic variations.
文摘A desorption isotherm is a very important basis in the understanding of drying process. In this study, the desorption isotherms from the sapwood of Mexican pine (Pinus pseudostrobus Lindl.) were determined by the gravimetric method (discontinuous control of sample weight) at 30℃ and 50℃. The salt method was used in the range of water activities from 0.11 to 0.89. The results show that the desorption ability of Mexican pine sapwood increased with temperature at a given relative humidity. The experimental data was further simulated with the models, i.e., BET, GAB, Oswin and Henderson models. The GAB, Oswin and Henderson models allow the representation of the entire desorption isotherms. The BET model showed a better fit for water activity lower than 0.35, with a mean relative deviation of 0.0286 at 30℃ and 0.0167 at 50℃. Simultaneously, the BET model gave a better representation of moisture content in the monolayer saturation region. Overall, the GAB model ensured the best simulation of the entire isotherm, while the Henderson model displayed the worst simulation.
基金Melbourne Water and an Australian Research Council Linkage(LP110200194).
文摘Aims Natural and anthropogenic changes in forests can have important influences on transpiration and water production.Understanding the effects of increasing disturbances,due for example to climate change and forest harvesting,requires detailed information on how forest density and structural attributes relate to transpiration.Mean annual transpiration of eucalypt forest communities is often strongly correlated with total cross-sectional sapwood area.Our aim was to test an efficient method for estimating sapwood area at_(1.3)m height(SA_(1.3))in a large number of trees to understand the spatial heterogeneity of tree and stand sapwood area within and between forest communities,and develop allometric relationships that predict SA_(1.3)with forest inventory data.We also apply tree competition models to determine the degree to which the relationship between SA_(1.3)and tree basal area at_(1.3)m height(BABA_(1.3))is influenced by competition.Methods We visited 25 recently harvested southeastern Australian forest sites consisting of 1379 trees and 5 Eucalyptus species to evaluate a new efficient data collection method for estimating SA_(1.3)with tree taper and stump dimensions data using mixed effects models.The locations of 784 stumps within one 5-ha site were accurately mapped using an unmanned aerial vehicle(UAV),and four distance-dependent tree competition models were applied across the site to explain within-stand variation in the ratio of SA_(1.3)to BABA_(1.3).Data from 24 additional sites,consisting of ten 15 m radial plots per site,were used to analyse within-site variation in R_(Ha)(the ratio of stand sapwood area SA_(Ha)to stand basal area BABA_(Ha)).The radial plots were merged within each site to evaluate between-site variations in R_(Ha)across the landscape.For predicting SA_(Ha)with forest inventory data,we computed the relationship between SA_(Ha)and a new index of total stem perimeter per hectare,defined as√BA_(Ha)N_(T),where N_(T)is tree stocking density.Important Findings Our 1379 measured stems represent the most comprehensive measure of sapwood area,surpassing the 757 measured stems in native eucalypt forests published in literature.The species-specific R_(Ha) varied considerably across sites and therefore extrapolating SA_(Ha)with spatially distributed BABA_(Ha)maps and a generalized R_(Ha) would introduce local uncertainty.We found that the species-specific stem perimeter index was more effective at capturing variability in SA_(Ha)across the landscape using forest composition,structure and density data(R^(2):0.72–0.77).The strong correlation between tree SA_(1.3)and BABA_(1.3)improved slightly using tree competition models(R^(2)increased from 0.86 to 0.88).Relating SA_(Ha)to routinely measured forest inventory attributes within permanent plots and Light Detection and Ranging(LiDAR)data may provide opportunities to map forest water use in time and space across large areas disturbed by wildfire and logging.
文摘Measurement of the longitudinal gas permeability was made for air-dried sapwood specimens from Masson pine (Pinus massoniana). Results showed that air-dried Masson pine sapwood was one of the most permeable softwoods. The investigated specimens had an average longitudinal gas permeability of 4.60 ×10-13 m3/m, and the permeability ranged from 1.06 ×10-13 to 1.12 ×10-12 m3/m. The Kruskal- Wallis Test indicated that, generally, there was no correlation between the longitudinal gas permeability and the trees from which specimens were prepared, and tree height had no significant effect on the longitudinalgas permeability.
文摘为了解喀斯特地区树种适应水分亏缺生境的内在机制,选择广西弄岗喀斯特森林9种主要树种,分析树种间水力结构及相关性状的差异及相关性。结果显示:供试9种树种间的最大边材比导率、最大叶片比导率、胡伯尔值、木质部导管直径及木材密度存在极显著(P<0.01)差异,其中,海南椴〔Diplodiscus trichospermus(Merrill)Y.Tang〕的最大边材比导率、最大叶片比导率以及木质部导管直径均最大,但胡伯尔值和木材密度最小。干季和湿季,供试9种树种间木质部导水率丧失百分比(PLC)均存在极显著差异,且金丝李(Garcinia paucinervis Chun et How)的PLC值均最高,分别为44.39%和38.92%。除闭花木〔Cleistanthus sumatranus(Miq.)Muell.Arg.〕、海南椴和淡黄金花茶(Camellia flavida Chang)外,其他6种树种PLC值在干季和湿季间无显著(P>0.05)差异,表明喀斯特地区树种耐干旱能力普遍较强。相关性分析结果表明:单叶叶面积与最大边材比导率、木质部导管直径和叶片净光合速率呈极显著(P<0.01)或显著(P<0.05)正相关,但与木材密度呈极显著负相关。综上所述,喀斯特地区木材密度较大的树种虽然耐旱性较强,但木质部水分运输效率会降低,进而使叶片净光合速率降低;反之,木材密度较小的树种虽然有利于木质部水分运输效率提高及碳固定,但是其耐旱性降低;水力结构功能特征间的关系既存在协同也存在一定的权衡。
