Plant Hydraulic Stress Explained Tree Mortality and Tree Size Explained Beetle Attack in a Mixed Conifer Forest

2019 ◽  
Vol 124 (11) ◽  
pp. 3555-3568 ◽  
Author(s):  
Xiaonan Tai ◽  
D. Scott Mackay ◽  
Brent E. Ewers ◽  
Andrew D. Parsekian ◽  
Daniel Beverly ◽  
...  
2006 ◽  
Vol 232 (1-3) ◽  
pp. 36-45 ◽  
Author(s):  
Dylan W. Schwilk ◽  
Eric E. Knapp ◽  
Scott M. Ferrenberg ◽  
Jon E. Keeley ◽  
Anthony C. Caprio

2006 ◽  
Vol 36 (12) ◽  
pp. 3222-3238 ◽  
Author(s):  
Leda Kobziar ◽  
Jason Moghaddas ◽  
Scott L Stephens

During the late fall of 2002 we administered three burns in mixed conifer forest sites in the north-central Sierra Nevada. Eight months later we measured fire-induced injury and mortality in 1300 trees. Using logistic regression, an array of crown scorch, stem damage, fuels, and fire-behavior variables were examined for their influence on tree mortality. In Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco), white fir (Abies concolor (Gord. & Glend.) Lindl.), and incense cedar (Calocedrus decurrens (Torr.) Florin), smaller trees with greater total crown damage had higher mortality rates. Smaller stem diameters and denser canopies predicted mortality best in ponderosa pine (Pinus ponderosa Dougl. ex P. Laws. & C. Laws). Duff consumption and bark char severity increased model discrimination for white fir and incense cedar and California black oak (Quercus kelloggii Newberry), respectively. In tanoak (Lithocarpus densiflorus (Hook. & Arn.) Rehd.), greater total crown damage in shorter trees resulted in higher mortality rates. Along with tree diameter and consumption of large (>7.6 cm diameter at breast height, DBH) rotten downed woody debris, fire intensity was a significant predictor of overall tree mortality for all species. Mortality patterns for white fir in relation to crown damage were similar among sites, while those for incense cedar were not, which suggests that species in replicated sites responded differently to similar burns. Our results demonstrate actual fire-behavior data incorporated into mortality models, and can be used to design prescribed burns for targeted reduction of tree density in mixed conifer forests.


1986 ◽  
Vol 16 (5) ◽  
pp. 1082-1087 ◽  
Author(s):  
Terri L. Thomas ◽  
James K. Agee

Prescribed fire was applied to a mixed conifer forest in southern Oregon, part of which was selectively logged in the 1930's. Structural effects were measured over a 4-year postfire period. Initial tree mortality was concentrated in small diameter and height classes of Abiesconcolor (Gord. and Glend) Lindl., Pinuslambertiana Dougl., and Pinusponderosa Dougl. Most mortality in all three species after the 1st year was associated with bark beetles. Mortality after 1 year for Abiesconcolor remained primarily in smaller tree classes, while both small and large pines were killed. Implications for restoring natural conditions in these ecosystems include recognizing structural as well as process goals, while reintroducing fire, and recognizing the significance of available prescription variables in the prediction of fire effects.


2010 ◽  
Vol 25 (3) ◽  
pp. 136-143 ◽  
Author(s):  
Gregory M. Filip ◽  
Helen M. Maffei ◽  
Kristen L. Chadwick ◽  
Timothy A. Max

Abstract In 2005, the 10-year effects of two silvicultural treatments (group-selection and shelterwood) on tree-growth loss and mortality caused by Armillaria ostoyae were compared with no treatment in a mixed-conifer forest in south-central Oregon. Ten years after treatment, Armillaria-caused mortality varied by species and was greatest in Shasta red fir (38% of trees per acre) and white fir (31%) and much less in Douglas-fir (3%) and ponderosa pine (0%). Ten years after harvesting, leave-tree mortality caused by Armillaria root disease was not significantly different in treated than in the unharvested units, nor was there significant diameter-growth response to the harvesting even in large ponderosa pine and Douglas-fir. The silvicultural treatments did have some benefits: (1) leave-tree mortality appeared, at least, not to be exacerbated by harvesting; (2) more disease-resistant pine, cedar, and larch seedlings and saplings survived in the shelterwood-harvest stands and group-selection openings than in comparable areas that were not harvested; and (3) living wood fiber was recovered from the treated stands, as well as dying and dead fuels that could exacerbate wildfire losses. Insights into host-pathogen interactions and recommendations for silvicultural options are presented. This is a case study from a single site and should be interpreted as such.


2010 ◽  
Vol 259 (5) ◽  
pp. 904-915 ◽  
Author(s):  
Siyan Ma ◽  
Amy Concilio ◽  
Brian Oakley ◽  
Malcolm North ◽  
Jiquan Chen

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