Wood Heat is Essential to Carbon Sequestration

by Jeff Rubin | December 9, 2019

Wood Heat is Essential to Carbon Sequestration

In order to avoid the worst effects of climate change we need to do two things: reduce pollution from heating our buildings, and maximize carbon sequestration in forests.

Part one: Reducing heating pollution

Central heating system distribution optionsMost heating pollution comes from America’s older, less efficient buildings built before 1980 and heated with central heating systems running an oil or gas furnace. These systems are designed to distribute high-temperature (140º-180ºF) air or water around the building. Even with weatherization, a cold climate heat pump (solar, geothermal, mini-split, etc.) can’t affordably keep up with the heat loss in these older buildings.

The idea that we should eliminate all combustion heating is a great goal, but like it or not, in the short term our only choices for America’s older buildings will continue to be combustion heat from oil, gas, or wood.

Every week, thousands of central heating boilers and furnaces are being replaced, many with gas (which is worse than oil despite Big Energy’s clean gas claims). Those heating systems are going to be pumping CO2 out of the ground and into the atmosphere for the next 25 years. We have two choices: fossil fuels (oil and gas boilers) that add to the total carbon in the atmosphere or wood pellet boilers, which releases less than half the carbon. At a minimum, heating with a wood pellet boiler or furnace reduces greenhouse gas emissions by ~60% when considering the life-cycle analysis of sourcing, processing, and transporting heating fuels.

And it’s not just lower carbon. The EPA holds high tech wood heating to a higher standard for  low particulates emissions than fossil fuels. Wood is a bridge fuel and, given the urgency of the climate crisis, we need to offset CO2 pollution from fossil fuel heating now.

Part two: Preservation versus conservation

Most US forest land is not protected. Here in the Northeast Wood Heat Region (NY, VT, NH, ME, & MA), 79% of forest is in private hands. Much of that is managed as working forest, mostly by individuals, not the forest products industry.

There is neither money nor will to preserve the vast amounts of forest that are in private hands. That’s not necessary. Our system of private property rights have lead private landowners to invest in management practices that have increased both the productivity and carbon sequestration of their wood lots.1

Over the past 65 years, healthy markets for forest products have driven the increase in forest lands and, with it, increased carbon sequestration. Not surprisingly, increased sequestration tracks with increased productivity and economic expansion. These increases in acreage, productivity, profitability, and sequestration are why private forests have sequestered more carbon than they’ve emitted.

Now all that is at risk.

The threat of development

That same system of private property rights means that to private land owners, their woodlot is an asset, and assets either need to earn their keep or get “reevaluated”. The real threat is permanently losing forested lands to development. That’s what’s happening now.

Currently, we are losing 22 acres of forest per day to development just in Vermont. Similar amounts are lost across the Northeast Wood Heat Region. Land clearing for development is another complex issue, but much of it comes back to the incentive for private landowners to maintain their woodlots in current use. Land is always more valuable when it’s developed. Because the lure of quick profits from converting woodland to development is a real and present danger, the key to conservation is healthy markets for all wood harvest—not just the 20% of high grade wood that ends up sequestered in buildings, furniture, and other wood products.

Markets for low-grade drive responsible forestry practices

70% of forest harvest is waste wood that can’t be used for building materials or furniture. In the Northeast Wood Heat Region, we have an abundance of this low-grade waste wood. It used to be used for making paper, but major losses to those markets (think smartphones) makes it more difficult for landowners to maintain their wood lots in current use. Leaving wood to rot on the forest floor still releases CO2 as the wood is broken down over time.

Effective utilization of waste wood drives responsible forest practices. In addition to disincentivizing development, responsible use of low-grade wood conserves wildlife habitat, water quality, air quality, and view sheds. Using clean-tech wood pellets and chips to heat our homes and businesses is better for the environment than oil or gas.

We need to take advantage of our opportunities to preserve important tracts of land while we concurrently support the conservation of working forests.

Part three: Conservation for maximizing sequestration and the carbon sink timeline

Biogenic carbon Vs. geologic carbon graphic
Biogenic carbon Vs. geologic carbon

Will switching from fossil fuels to automated wood pellet heating systems adversely impact the important role America’s forests play in sequestering carbon? We only have 10 years to avoid the worst effects of climate change and trees absorb carbon slowly, but release it quickly when used for heating—people refer to that carbon dynamic as “slow in, fast out”. It’s a legitimate concern, but it’s a pretty simplistic view of a very complex system.

It’s counterintuitive, but the sentiment that “we only have 10 years and that’s why we shouldn’t cut any trees now—because we don’t have 50 years to recover that carbon” is exactly what will lead to dangerous levels of deforestation and CO2 in the atmosphere.

The 2007 “IPCC Assessment (Intergovernmental Panel on Climate Change) states that long-term cumulative CO2 emissions — the emissions that are ALWAYS REDUCED by using forest biomass to produce energy — are CORRELATED with Projected Peak Global Temperature. So if we want to limit global temperature increases to 1.5 degrees centigrade or 2 degrees Fahrenheit, we need to use forest biomass… because doing so reduces long-term cumulative CO2 emissions.”1

A managed forest does more to draw down carbon in the atmosphere than a forest we leave untouched.

Managed forests continue to grow and sequester carbon. Removing select trees from an overcrowded stand can release the residual stand and increase the amount and quality of wood grown (and amount of carbon sequestered) in subsequent years as compared to a stand that was not thinned.

“In the long term, a sustainable forest management strategy aimed at maintaining or increasing forest carbon stocks, while producing an annual sustained yield of timber, fibre, or energy from the forest, will generate the largest sustained mitigation benefit.”
Source: Energy Policy and Climate Change IPCC (4th Assessment Report)

The bottom line is that a managed forest does more to reduce greenhouse gas emissions than an unmanaged forest, and that even though we only have 10 years to turn the tide on climate change, the essential context for forest carbon drawdown is in the 20 to 50 year window according to the IPCC.

The short term risk is not the sudden release of carbon stored in trees. The short term danger is in losing forest land permanently to development because we have not incentivized the use of forest products, and low-grade waste wood in particular.

True (carbon) cost accounting

What is the true cost of all the greenhouse gasses (not just the CO2) released from the three available heating fuels? The essential context is one of real world alternatives. Since the Northeast Wood Heat Region has such a large percentage of private forest, low-grade waste wood that needs a market, and buildings that rely on high temperature distribution systems, it doesn’t make much sense to pull oil and gas out of the ground for heat.

Part four: Ensuring responsible procurement of wood heating fuel

In order for all this to be true, we need to sustainably manage our forests. According to actual forest inventories (as opposed to modeling or projections), the private landowners of this country have been doing that for decades. We currently have a system of federal, state, and local laws and best management practices that ensure they would be able to continue to do so as long as the market demand exists. That’s where consumer choice can make a dent in the climate crisis.1

We should take our cue from CSAs (Community Supported Agriculture) and empower a new subcategory of civic agriculture: Community Supported Forests (CSF)! The Northeast Wood Heat Region is the ideal seabed for an alternative model of a carbon economy based on connecting the producers and consumers of advanced wood heating. In the process, we strengthen a sense of community through local markets2, while working both sides of the climate equation—lowering GHG emissions and increasing carbon drawdown by incentivizing long-term carbon sequestration.

Groups like the Forest Stewardship CouncilCertified Family Forests and the Sustainable Forestry Initiative give consumers the power to incentivize responsible, sustainable forest practices by prioritizing products that come from certified sources.

An even more local community-centric model

Individual communities are figuring out how to develop their own community energy plans that connect their school or municipal buildings with local, sustainably managed woodlots. In Vermont, the Mt. Abraham Unified High School uses a SELF standard that gives landowners a financial incentive to engage in sustainable forest management. SELF stands for Sustainable, Efficient, Local and Fair.

A project of the Forest Stewards Guild and the Yale School of Forestry and Environmental Studies, the steps to create a reliable supply of wood chips can be found in the publication, Harnessing the Power of Local Wood Energy.

Part five: Climate Advocacy with Agency!

The Northeast Wood Heat Region is a model of public/private partnership with state incentives for wood pellet heating systems, a proven track record of sustainable forest management, and millions of dollars invested by private industry. The wood pellet boiler and furnace industry have built out the infrastructure to deliver the automated, hands-off convenience we’ve come to expect from our heating systems. They’ve invested millions in proven technology with lower emissions than oil or gas. Now it’s up to us.

We can have a distributed system of clean heating instead of the dirty, polluting centralized fossil fuel heat that got us into this climate mess. We can choose a polyculture based on conservation of renewable resources instead of a fossil fuel monoculture that works to pass our climate problem to the next generation. We can reduce heating pollution today while conserving a vital carbon sink for the future. That is why modern automated clean wood heat is essential to carbon sequestration.

1. The Science of Forest Biomass Energy by Robert W. Malmsheimer Professor of Forest Policy and Law, State University of New York, College of Environmental Science and Forestry Syracuse, NY. It is is based on an assessment, analysis, and summary of more than 135 scientific peer-review articles.
2. Obach, Brian K.; Tobin, Kathleen (2014-06-01). “Civic agriculture and community engagement”. Agriculture and Human Values. 31 (2): 307–322. doi:10.1007/s10460-013-9477-z. ISSN 0889-048X.

Heat Loss

The two variables of of heat loss are a) geographic location, and b) building performance. Together they will determine the quantity of heat needed to maintain comfort.

Geographic location drives the building's “design day." Your design day is the difference in temperature between the inside and outside of your house on the theoretical coldest day of the year; so in the northeast we calculate a day that is -10ºf outside and comfortable 68ºf inside. This is referred to as the “delta-T” value. A typical delta-T for the northeast is 78º.

Building performance is the big one because there’s nothing we can do about geographic location. Today we can build a really tight thermal envelope, but most of our heating pollution comes from the millions of homes built over the last 100-150 years. We are getting better at buttoning-up those old buildings with insulation and weather sealing but weatherization is still  never going to be enough to overcome the heat loss from a 78º delta-T. That means we need heating systems that can quickly put a whole lot of heat back into those old houses on the days that are really cold.