The Plant a Trillion Trees Campaign to Reduce Global Warming – Fleshing Out the Concept

Abstract

The campaign to plant a trillion trees provided an easily understood approach to reduce the threat of global warming. However, focusing on trees does not consider that a maturing forest releases carbon (C) from dying trees offsetting C intake from growth of other trees, and results in only a one-time carbon storage benefit. Under sustainable management that harvests before forest growth slows down, forest C is transferred to wood products that substitute for fossil fuel (FF)intensive products, reducing the carbon dioxide (CO 2 ) emissions with every harvest. Sustainably managed forests maintain growth by replanting (or regenerating), sustaining the C stored in products, as well as avoiding FF-intensive product emissions with every harvest. This paper addresses the question: Could planting more trees significantly reduce atmospheric CO 2 ; and if so, how? Survey data from many wood-producing mills show life cycle inventory (LCI) data on C that has been tracked through every stage of processing for many different wood products specific to each United States (USA) supply region, as well as C displacement measurements when substituting wood for FFintensive products. Results show that more and better-managed forest lands and more efficient product uses provide significant opportunities to reduce CO 2 emissions, especially in highly productive forest regions.

Comparative LCAs of Conventional and Mass Timber Buildings in Regions with Potential for Mass Timber Penetration

“…Atmospheric carbon dioxide is the major contributor to global warming, making carbon emissions one of the world's most urgent environmental challenges. Recent research has indicated that afforestation can offer the single greatest opportunity for carbon mitigation [1][2][3]. However, delivering on this potential implies the afforestation of hundreds of millions of hectares in the next decade [4].…”

“…For each metric ton (ton) of carbon stored in trees, 3.67 tons of carbon dioxide emission is removed. As forests age, their initially high carbon sequestration rates decrease, and eventually, carbon flux (i.e., sequestration and release) reaches a balance [3]. After disturbances, much of the stored carbon may be released back into the atmosphere relatively quickly via increased mortality, fire, or decomposition.…”

“…After disturbances, much of the stored carbon may be released back into the atmosphere relatively quickly via increased mortality, fire, or decomposition. Recent controversies about how forests best can offset carbon emissions have focused on the question of whether or not forests can increase their positive contribution to the carbon cycle if trees are harvested and the sequestered carbon is stored in long-term products, such as buildings [3,[5][6][7].…”

“…Cross-laminated timber is a relatively new product, and research is ongoing to track how production changes and building designs result in lower embodied carbon than conventional materials and designs [12][13][14]25]. Clearly, CLT buildings have potentially greater benefits if efficient reprocessing at the end of building service life is implemented for reuse and recycle [3]. Increased benefits are also manifested when the timing of emissions is considered [12,27].…”

“…Building with wood provides an important climate change mitigation opportunity by storing carbon for decades and displacing emissions from nonrenewable materials together with reducing dependence on nonrenewable resources. Taking advantage of this opportunity requires sustainable forest management, which ensures that carbon sequestration is optimized in the forest while increasing carbon pools in harvested wood products for long-term storage [3,5,[30][31][32][33] (Gu Johnston perez). This study is the first step in filling the knowledge gap on comparing functionally equivalent conventional buildings to those constructed using MT.…”