David Ross, MF

2011 TRI Fellow in Israel

Assessing Silvicultural Treatments on Semi-Arid Forests in Northern Israel to Reduce Vulnerability to Catastrophic Wildfires and Enhance Carbon Stocks


The goal of my summer research was to measure the relative stocking density, basal area, and above-ground biomass of two forest types within the Mount Carmel Forest in northwestern Israel, which underwent a catastrophic fire event in December of 2010. Both forest types exhibited similar species compositions of native pine and oak, yet differed strikingly in their history and management strategy: one was planted between 30-50 years ago and has experienced a regular thinning regime, while the other is largely believed to be of “natural” origin and has seen only minor pruning. Over 40 distinct native pine stands were sampled for DBH and height, with a minimum of three 1/5 acre plots per stand, for a total of nearly 150 plots. I hypothesized that the planted stands were less dense, due to the regular thinning management regime. An additional hypothesis was that the thinned forests had a lesser percentage of trees killed, which will be tested by future interpretation of third-party remote sensing data.

By understanding the stocking density, basal area, and biomass in the two forest types, one can make assumptions and comparisons regarding vulnerability to future wildfires. While the data have not yet been fully analyzed, preliminary indications show that both hypotheses were correct. From a climate change perspective, thinning forests is often thought of as exacerbating climate change due to the net decrease in “carbon stocks”, as trees are a major sink for carbon dioxide. This research, however, may lead to the growing argument in favor of active thinning of forests with periodic fire regimes, as harvesting actually leads to more resilient forests that are less vulnerable to wildfire. Should the hypotheses prove true, it can be inferred that thinning leads to a net gain of carbon permanence, i.e. the likelihood that the forest will not be destroyed by future wildfires.