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Drought Impacts and Compounding Mortality on Forest Trees in the Southern Sierra Nevada
- Source :
- Forests, Vol 10, Iss 3, p 237 (2019)
- Publication Year :
- 2019
- Publisher :
- MDPI AG, 2019.
-
Abstract
- The increase in compounding disturbances, such as “hotter droughts” coupled with insect outbreaks, has significant impacts on the integrity of forested ecosystems and their subsequent management for important ecosystem services and multiple-use objectives. In the Southern Sierra Nevada, years of severe drought have resulted in unprecedented tree mortality across this mountainous landscape. Additionally, past land management practices, including fire suppression, have led to overly stocked, homogenous forest stand structures, dominated by small diameter, shade-tolerant and fire-intolerant tree species. Thus, the current condition of the landscape has further increased the susceptibility of forest trees to multiple stressors. We sought to determine the effects of extreme drought and insect outbreaks on tree mortality and their influence on forest stand structure and composition. To characterize mortality patterns, we monitored the condition of mature forest trees (>25.4 cm diameter at breast height) across 255 monitoring plots with four repeated measurements from 2015 through 2017. Tree mortality varied by species and through time. Reductions in pine species (Pinus lambertiana Douglas and P. ponderosa Lawson & C. Lawson) occurred earlier in the study period than Abies concolor (Gord. & Glend.) Lindl. Ex Hildebr. or Calocedrus decurrens (Torr.) Florin. Across species, larger tree size, most often associated with tree height, was consistently related to increased survival in mature, overstory trees. As expected, sites with greater pine stocking and subsequently more bark beetle (Curculionidae: Scolytinae) host availability had increased pine mortality, especially for P. ponderosa. For Abies concolor, lower overstory basal area increased tree survival for this species. This study highlights the importance of effective forest monitoring, especially during a period of unprecedented ecological change as the compounding disturbance had a disproportional effect on pine species in smaller diameter classes. Proactive forest management may be necessary to maintain and promote these ecologically important species in heterogeneous mixtures across the landscape.
- Subjects :
- 0106 biological sciences
adaptive management
Bark beetle
Collaborative Forest Landscape Restoration Project
010504 meteorology & atmospheric sciences
Forest management
Red fir
010603 evolutionary biology
01 natural sciences
Calocedrus decurrens
Basal area
Stocking
Incense-cedar
0105 earth and related environmental sciences
White fir
biology
Sugar pine
Ponderosa pine
Abies concolor
Diameter at breast height
Forestry
lcsh:QK900-989
biology.organism_classification
California black oak
monitoring
Disturbance (ecology)
lcsh:Plant ecology
Subjects
Details
- ISSN :
- 19994907
- Volume :
- 10
- Database :
- OpenAIRE
- Journal :
- Forests
- Accession number :
- edsair.doi.dedup.....1fd051023d8a54fb3dcb7b17580526e6
- Full Text :
- https://doi.org/10.3390/f10030237