What about heating my home with a wood burning stove?
Philosophically, burning wood for energy or heat should be sustainable because the tree absorbed carbon all its life, then when it is burned that carbon is released which means a neutral net carbon emission. This was probably the case many hundreds of years ago before deforestation and carbon accumulation were the reality. Now however, the situation is more complicated than that simple balanced cycle would suggest.
When a log is burned today, it will release more carbon per BTU of heat energy than any fossil fuel and almost twice that of natural gas. Those emissions are additional to the carbon that has already accumulated in the atmosphere causing global warming. If a tree is planted when that log was harvested for burning it will be decades until the carbon released from burning the log is reabsorbed by the new tree. That assumes that the newly planted tree will be allowed to grow undisturbed for 50 years or so to enable that absorption to happen. So in the very best case scenario, when we burn wood we are adding to the problem now in the hope that it will be balanced out decades from now. At this time when we need to be reducing or eliminating emissions, this is a losing proposition.
On top of this, burning wood releases other problematic emissions beyond carbon dioxide. Even the best wood stoves release nearly one hundred times more pollutants like benzene, formaldehyde and fine particulates than a natural gas furnace. These pollutants are carcinogenic, contribute to respiratory disease, heart attacks, smog formation, etc. The black carbon or soot that is produced by burning wood is also a potent contributor to global warming in addition to the carbon dioxide released. A heat pump furnace releases zero of these pollutants. Here is a good link on the dangers of wood smoke to our health and the environment. Families for Clean Air.
The best thing to do with tree logs and debris from trees is to chip it or compost it. Composting will release some methane as the material decays, but it will be far less than the equivalent carbon emissions from burning - roughly one sixth as much. In addition, composting returns carbon and other important nutrients to the soil whereas burning does not. Here is a good article on that from The Sierra Club.
What about gas powered lawn mowers and leaf blowers?
Relative to automobiles, gas powered lawn and garden equipment produce far fewer total carbon emissions, but they still add significantly to the problem with carbon accumulation and also with deteriorating air quality in urban areas. The US Department of Energy estimates that 1.2 billion gallons of gasoline are consumed annually in the US for lawn care. This translates to nearly 12 Million tons of CO2 emitted per year.
Gas powered lawn and garden equipment is fast becoming the number one contributor to smog forming air pollution. The small engines in lawn mowers and leaf blowers emit hundreds of times more pollutants per hour than automobile engines. The California Air Resources Board projects that total smog forming pollution from small engines will exceed those from passenger cars in California by 2020. These pollutants - benzene, butadiene, formaldehyde, oxides of nitrogen, carbon monoxide and small particulates are known carcinogens and known respiratory, cardiovascular and neurological health risks. The EPA considers gasoline powered lawn and garden equipment “an important source of dangerous air pollution.”
New lithium battery powered lawn mowers and leaf blowers compete effectively with gasoline powered tools regarding power and performance and have significantly longer operating run times than older electric models. For most households these electric tools will perform well, will be cheaper to operate, will require no maintenance, and will eliminate messy gasoline and oil filling. On top of that these new tools are quieter and will not produce the lingering gasoline smells that are an annoying indicator of the lethal fumes and pollution that gasoline powered equipment produce. If you have a larger yard, opt for a model with a larger battery - 5.0 - 7.5Ah.