Radial variation in sap flux density (SFD) as a function of sapwood thickness is of importance in accurately estimating sap flux through sapwood area which, in turn, decides the precision of heat pulse application. Ho...Radial variation in sap flux density (SFD) as a function of sapwood thickness is of importance in accurately estimating sap flux through sapwood area which, in turn, decides the precision of heat pulse application. However, until now, only a few studies have evaluated the magnitude and significance of sampling errors associated with radial gradients in SFD, which were based on the small monitoring measurement data from a few trees. Based on one year of heat pulse observation of two 3 - 4 years old Eucalyptus urophylla S. T.,P Blake plantations in Leizhou Peninsula, Guangdong Province, China, a way of data processing was developed to treat with the lots of SFD data measured from 39 trees. It was found that the radial variation in SFD as a function of sapwood thickness in the two eucalyptus plantation sites could be expressed as y = 3. 667 5x(3) - 7.295 5x(2) + 3.682 6x + 0. 567 4 (R-2 = 0. 939 1, n = 80, P = 0.01), where y is the ratio of SFD of a sensor to the average of four data in different depths, x is the ratio of a sensor depth to tire radial sapwood thickness. It was the same (as in the following equation) in Jijia site, y = 5.006 2x(3) - 9.116 1x(2) + 4. 454 4x + 0.463 4 (R-2 = 0. 806 9, n = 72, P = 0.01) in Hetou site. From cambium to heartwood, SFD showed some increases at first and then decreases continuously. However, because die trees were very young, the maximum SFD was only 0. 33 - 0. 36 times more than the minimum.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 Kamataka covering different age groups （11-36 years）,...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 Kamataka covering different age groups （11-36 years）, density （516-2061 trees/ha） and sites. From these planta- tions, 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 con- tent were analyzed by sampling five trees each from two different planta- tions, one 30 years old at 553 trees.ha-1 and the other 32 years old at 911 trees.ha-1. The highest heartwood proportion of stem wood volume （over-bark） was 56.3% and the lowest was 37.1%.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-destructi...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 （p0.05） 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
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
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 gr...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 softwood...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 inv,,stigated specimens had an average longitudinal gas permeability of 4.60 ×10^13 m^3/m, and the permeablity ranged from 1.06×10^-13 to 1.12×10^-12 m^3/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 longitudinal gas permeability.展开更多
文摘Radial variation in sap flux density (SFD) as a function of sapwood thickness is of importance in accurately estimating sap flux through sapwood area which, in turn, decides the precision of heat pulse application. However, until now, only a few studies have evaluated the magnitude and significance of sampling errors associated with radial gradients in SFD, which were based on the small monitoring measurement data from a few trees. Based on one year of heat pulse observation of two 3 - 4 years old Eucalyptus urophylla S. T.,P Blake plantations in Leizhou Peninsula, Guangdong Province, China, a way of data processing was developed to treat with the lots of SFD data measured from 39 trees. It was found that the radial variation in SFD as a function of sapwood thickness in the two eucalyptus plantation sites could be expressed as y = 3. 667 5x(3) - 7.295 5x(2) + 3.682 6x + 0. 567 4 (R-2 = 0. 939 1, n = 80, P = 0.01), where y is the ratio of SFD of a sensor to the average of four data in different depths, x is the ratio of a sensor depth to tire radial sapwood thickness. It was the same (as in the following equation) in Jijia site, y = 5.006 2x(3) - 9.116 1x(2) + 4. 454 4x + 0.463 4 (R-2 = 0. 806 9, n = 72, P = 0.01) in Hetou site. From cambium to heartwood, SFD showed some increases at first and then decreases continuously. However, because die trees were very young, the maximum SFD was only 0. 33 - 0. 36 times more than the minimum.
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 Kamataka covering different age groups （11-36 years）, density （516-2061 trees/ha） and sites. From these planta- tions, 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 con- tent were analyzed by sampling five trees each from two different planta- tions, one 30 years old at 553 trees.ha-1 and the other 32 years old at 911 trees.ha-1. The highest heartwood proportion of stem wood volume （over-bark） was 56.3% and the lowest was 37.1%.
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 （p0.05） 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.
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 inv,,stigated specimens had an average longitudinal gas permeability of 4.60 ×10^13 m^3/m, and the permeablity ranged from 1.06×10^-13 to 1.12×10^-12 m^3/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 longitudinal gas permeability.
