I\u2019ve been meaning to get to the bottom of my burn-wood pile, reuse the excess lumber in my garage, and plant some new trees in my Oakland neighborhood. California\u2019s Environmental Protection Agency\u2019s climate action department\u2019s been thinking the same thing. While trying to work out a verifiable market in carbon offsets--the credits you can buy, for instance, to offset that plane flight to England--the state is trying to expand the definition of what could qualify as an offset. The first round was the obvious one. The target is expanding current private forest lands to create bigger carbon sinks. (Trees suck in CO2 from the atmosphere and \u201csequester\u201d it within their cell structures.) That plan is on its way. Now, the state\u2019s considering parameters that may be used to offset carbon with urban forestry (like my new neighborhood trees), non-forestland (like oak landscape), fireplace wood that replaces fossil fuel use, and refuse wood that is kept out of landfills. The latter, once dumped, adds to the greenhouse gas methane in landfills during anaerobic degradation. Figuring out the quality of those tree castoffs to measure potential offsets was the subject of a CalEPA workshop earlier this month. For centuries, Californians have burned refuse wood--prunings, trees cleared for other land use--in outdoor piles. The energy is unused and the resulting carbon emissions contribute to global warming. The timber industry used to do the same with teepee burners. The top third of the state often had the scent of lumber mill burns. That\u2019s history. Yet, it wasn\u2019t all that long ago too that rice stumps were burned openly in the state, contributing not only to global warming, but to eye-stinging and lung burning air. Without teepee burners, some of the shavings and odd pieces after lumber mills plane two-by-fours or other dimensional lumber end up in biomass power plants. A lot of the refuse wood, however, ends up in landfills. CalEPA is trying to figure out how to account for any refuse wood, new urban trees, and oak woodlands for carbon offsets. It\u2019s a lot of guesswork. It\u2019s also lower down on the list of priorities to set up parameters for a market in offsets. Now, the forest-for-the-offset-trees are fairly clear. These are more remote, and more difficult to measure, potential offsets. When I decide to fire up my (efficient) wood stove, I use orchard wood--mainly almond. My personal carbon offset is that for every tree that\u2019s died or removed, another one is planted. Unless, of course, it succumbs to suburban development. But in this housing market, that\u2019s unlikely in the short term.