Presentation Type

Poster

Abstract

I studied mountain pine beetle (Dendroctonus ponderosae) attacks in ponderosa pine (Pinus ponderosa) to determine how attacks are distributed through a stand, how growth rate affects a tree’s likelihood of being attacked, and if there is a genetic basis for susceptibility to attack. I used a genetic trial of ponderosa pine planted in 1974 at Lubrecht Experimental Forest in northwestern Montana made up of about 4000 trees from 204 distinct genetic families. Mountain pine beetles attacked the trial during an outbreak that started in 2000 and continues today. I recorded whether or not beetles had successfully attacked each tree and mapped the results. In 2001 foresters measured the height and diameter at breast height (DBH) of each tree, and I used these measurements as growth rate. Attacked trees had more neighbors that were attacked than un-attacked trees, meaning attacks occurred in clusters. I controlled for this spatial pattern by counting the number of attacked neighbors each tree had. I found that some families were attacked more often than average, and the opposite was true for other families. Trees with larger DBHs were more likely to be attacked. These results suggest that a tree’s susceptibility to attack depends on genetic source as well as growth rate and location. I identified families that were more or less likely to be attacked, and these families can be researched further.

Category

Life Sciences

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Apr 11th, 3:00 PM Apr 11th, 4:00 PM

Which Trees Do Mountain Pine Beetles Attack?

I studied mountain pine beetle (Dendroctonus ponderosae) attacks in ponderosa pine (Pinus ponderosa) to determine how attacks are distributed through a stand, how growth rate affects a tree’s likelihood of being attacked, and if there is a genetic basis for susceptibility to attack. I used a genetic trial of ponderosa pine planted in 1974 at Lubrecht Experimental Forest in northwestern Montana made up of about 4000 trees from 204 distinct genetic families. Mountain pine beetles attacked the trial during an outbreak that started in 2000 and continues today. I recorded whether or not beetles had successfully attacked each tree and mapped the results. In 2001 foresters measured the height and diameter at breast height (DBH) of each tree, and I used these measurements as growth rate. Attacked trees had more neighbors that were attacked than un-attacked trees, meaning attacks occurred in clusters. I controlled for this spatial pattern by counting the number of attacked neighbors each tree had. I found that some families were attacked more often than average, and the opposite was true for other families. Trees with larger DBHs were more likely to be attacked. These results suggest that a tree’s susceptibility to attack depends on genetic source as well as growth rate and location. I identified families that were more or less likely to be attacked, and these families can be researched further.