Last week I assisted Lava Lake Science and Conservation field technician Justin Stevenson with aspen, Populus tremuloides, stand monitoring on the Lava Lake property. Beginning in 2006, we have monitored a number of aspen stands to assess the effectiveness of our grazing management practices and the health of the stands. Monitoring entails selecting multiple 100 foot transects that run at a predetermined bearing through the stand. Of the three monitoring sites we visited in the Copper Creek drainage, two sites contained three transects and one contained two.
Using GPS points and historical photos from the 2006 monitoring, we located the beginning and end of each transect. Once a tape had been strung between the two points, we counted and categorized each aspen within three three feet of either side of the tape. Within the monitoring transects the aspens varied in size from seedlings with only a few leaves to towering trees.
A healthy aspen stand contains trees at every level of development, which creates a continuous canopy from the ground up. Since aspen grow from the top, or terminal bud, it is imperative that some portion off the seedling be given the opportunity to grow above the browsing height. When browsing pressure increases no smaller trees are able to attain this critical height and breaks begin to appear in the vertical canopy. With continued heavy use eventually an aspen stand will contain only tall mature trees, those that were above browsing height when the browsing started.
Rehabilitating these heavily used stands with only mature trees is a long term process. During our monitoring trip we were able to see the positive results of over 10 years of our sustainable grazing management practices. Just by looking at the photos from 2006, it is possible to see the rehabilitation of the understory in these stands. It was a perfect September day to be out in the field and a great opportunity to take part in the restoration and monitoring that is occurring throughout Lava Lake Ranch.