TY - JOUR
T1 - Evaluation of predictive models for Douglas-fir bark thickness at breast height following 12 biomass harvest treatments
AU - Jang, Woongsoon
AU - Keyes, Christopher R.
AU - Graham, Jonathan M.
N1 - Publisher Copyright:
© 2015 Elsevier Ltd.
PY - 2016/1/1
Y1 - 2016/1/1
N2 - Foresters often require an estimation of bark thickness from a reference height (typically breast height) to accurately estimate the bark or wood volume of a tree. Various models for estimating the bark thickness of interior Douglas-fir (Pseudotsuga menziesii var. glauca) from measured dbh (diameter at breast height) were evaluated. Sample trees were from northern Rocky Mountain mixed conifer stands that had been subjected to four levels of experimental woody biomass harvesting. Among simple linear, nonlinear, and segmented linear mixed effects models, the segmented linear model performed best. A join point (where the linear equations are linked) for the segmentation was statistically detected at approximately 19.0 cm dbh. The join point seems to indicate the size at which juvenile Douglas-fir trees boost the production of bark tissue, perhaps as those trees express dominance over competing understory vegetation. Woody biomass utilization level had no impact on bark thickness, indicating that the bark:dbh relationship does not depend on biomass utilization intensity. The study results enable accurate bark thickness estimation for interior Douglas-fir in this region, and suggest several silvicultural applications for juvenile Douglas-fir stand management.
AB - Foresters often require an estimation of bark thickness from a reference height (typically breast height) to accurately estimate the bark or wood volume of a tree. Various models for estimating the bark thickness of interior Douglas-fir (Pseudotsuga menziesii var. glauca) from measured dbh (diameter at breast height) were evaluated. Sample trees were from northern Rocky Mountain mixed conifer stands that had been subjected to four levels of experimental woody biomass harvesting. Among simple linear, nonlinear, and segmented linear mixed effects models, the segmented linear model performed best. A join point (where the linear equations are linked) for the segmentation was statistically detected at approximately 19.0 cm dbh. The join point seems to indicate the size at which juvenile Douglas-fir trees boost the production of bark tissue, perhaps as those trees express dominance over competing understory vegetation. Woody biomass utilization level had no impact on bark thickness, indicating that the bark:dbh relationship does not depend on biomass utilization intensity. The study results enable accurate bark thickness estimation for interior Douglas-fir in this region, and suggest several silvicultural applications for juvenile Douglas-fir stand management.
KW - Bark thickness
KW - Biomass harvesting
KW - Interior Douglas-fir
KW - Northern Rocky Mountains
KW - Segmented linear regression
UR - http://www.scopus.com/inward/record.url?scp=84949292718&partnerID=8YFLogxK
U2 - 10.1016/j.biombioe.2015.11.015
DO - 10.1016/j.biombioe.2015.11.015
M3 - Article
AN - SCOPUS:84949292718
SN - 0961-9534
VL - 84
SP - 118
EP - 123
JO - Biomass and Bioenergy
JF - Biomass and Bioenergy
ER -