| dc.description.abstract | The spruce beetle (Dendroctonus rufipennis) is a natural part of the
western North American landscape, feeding on the phloem of trees in the Picea
genus. The spruce beetle generally feeds on downed trees but can also feed on
standing living trees if beetle populations and host trees are plentiful. If this
occurs, it can result in an outbreak of spruce beetle populations. With the help of
blue-stain fungi, these outbreaks can cause high mortality in spruce tree
populations and devastate forests. Multiple factors can contribute to an outbreak
of spruce beetle, with most linked to climate change. The government of British
Columbia has a list of management practices to mitigate the effects of the
spruce beetle, but prevention remains elusive. It is known that a more diverse
tree stand can mitigate severity of insect attacks, most notably for spruce beetle
if there are more diverse coniferous species. Here, an assessment of five blocks
of forest set for harvest in two different areas with different levels of tree species
diversity in the Omineca landscape unit of BC agrees with these results. The two
areas in the Omineca landscape unit consisted of the Mischinsinlinka (MIS) area
with low tree diversity and the Gaffney (GAF) area with high tree diversity. The
MIS area, which had only two prominent tree species on the sites, experienced
high amounts of beetle predation. The GAF, with up to four prominent species of
trees, had lower amounts of beetle predation. It was also discovered that the
correlation between tree diameter at breast height (DBH) and tree height to
beetle attack severity is much stronger in the MIS than the GAF. This suggests
that damage correlation is strongest in less diverse stands and less so in more
diverse stands. | en_US |
