Impact Estimations & Conversions - Forestmatic

Forestmatic Impact Estimations & Conversions

Updated 14/12/2020


Introduction

We take transparency very seriously. This is the reason why we want to provide our community with all necessary tools to understand their impact. Forestmatic provides data on the reforestation impact and associated proxies users have contributed to. This document is the basic foundations for all the estimations performed by Forestmatic, in an attempt to show the most accurate and relevant information to our community.

Reforestation Sites

Our reforestation sites are managed by our partner Kijani Forestry and based in Uganda, Gulu district. To maximize the impact of our reforestation activities, permanent nurseries and training facilities are established in rural communities. Nursery Hubs are high-output nurseries that provide diverse seedlings, agroforestry trainings, and employment to vulnerable communities. Shareholder farmers are provided with tools to reforest their degraded land and build capacity for long-term income and wealth generation by means of long-term market access for fuelwood, fruit, timber and improved crops.

Why Uganda?

51% of Uganda’s forest land has been clear-cut in the last 3 decades and it is estimated that by 2050 there will be no forested land left. 85% of Ugandans are subsistence farmers, farming on depleted land and growing low-market value crops. 97% of Ugandans rely on unsustainably sourced cooking fuel from firewood or charcoal. Charcoal prices have more than doubled over the last five years as fuelwood becomes increasingly scarce from deforestation. Without trees, soil quality is depleting, and crop yields are decreasing. With most Ugandans surviving off subsistence farming, income levels are suffering huge backlashes. Through Kijani’s contribution we address both the severe deforestation in the region and the persistent cycle of poverty the community faces thus creating a social and environmental impact by:

Growing economically-viable fruit, timber, and fuelwood trees that can raise shareholder farmers out of poverty.

Planting trees that increase soil quality, capture CO2, and regrow from the existing root structure (coppicing) when harvested for charcoal production.

Introducing inexpensive, high-efficiency kilns to create more charcoal from the same amount of wood

By paying fair or above-market prices for goods and providing income generating tools, farmers can systematically grow out of poverty. With just one year of planting, we project each household can earn an additional $6,500 over 10 years, representing a +430% in income.

Environmental Impact Estimations

The carbon impact occurs through planting trees and saving trees that would have been cut for charcoal usage, thus reducing emissions from deforestation and forest degradation. This page will summarize the research from one of our primary species, Gmelina arborea.

1.0 - Yearly average CO2 absorbed by 1 tree

The yearly average CO2 absorbed by a tree is not an easy assessment to make. In order to do so, there are different methodologies. The regulated and voluntary carbon market use very specific frameworks in order to operate accurate and comparable analysis.
We operate using the extensive bibliography and research available, thus providing estimations based on the general voluntary market approach. In this context, we estimate that yearly average CO2 absorbed by a tree is:

1.1 - Soil and root permanent sequestration

Roots - Average of 0.98 kg biomass per tree annually
Soil - Average of 1.21 kg biomass per tree annually ~1.7 kg CO2 sequestered per kg of biomass produced
Total - Average of 3.76 kg permanent CO2 sequestration per tree annually

1.2 - Avoided emissions through efficient charcoal

Stems - Average of 9.47 kg per tree annually
Branches - Average of 3.76 kg per tree annually
Total - Average of 13.2 kg biomass per tree per year

1.3 - Carbon impact through improved kiln efficiency

Traditional kilns - 18% yield equalling 5.6 kg wood per kg charcoal
Kijani's kilns - 37% yield equalling 2.7kg wood per kg charcoal 2.9 kg wood saved per kg charcoal.
G. arborea - is 47% carbon. 3.67 kg CO2 is taken from the atmosphere to produce each kg carbon of wood while 2.67 kg of O2 is released.

Subtotal - 4.88 kg CO2 avoided for each kg charcoal made 4.88 kg avoided / 3.47 kg wood = 1.41 kg CO2 saved for each kg wood grown for charcoal

Total - average of 18.9kg CO2 emissions avoided per tree annually

Accounting for a trees survival rate of 90% we adjust these totals from the theoretical sequestration summing up the permanent sequestration and avoided CO2 emissions:

Mature Tree - 22,65 kg of CO2

Sapling Tree - 6 kg of CO2

More information found at the following sources: source 1 and source 2.

2.0 - Average Car CO2 emissions per km

CO2 metrics are generally a very hard metric to represent. There are not much references for the general public, and the gigantic numbers we are used to look at in scientific researches and papers are very hard to represent. To overcome this situation, we wanted to reference some real life example, something everyone could relate to: cars. Car CO2 emissions are estimated around 120gr/km. Therefore:

Mature Tree - 188,75 km compensated

Sapling Tree - 50 km compensated

More information found at the following source: source 1.

3.0 - Average Oxygen (O2) supply needed

There are different approaches to calculate the average O2 supply of a tree. One approach could take into account the net oxygen production, which is the amount made during photosynthesis minus the amount the tree uses. Another calculation would compare the net oxygen production in terms of gas available for humans to breathe. The following calculation looks at the average amount of oxygen saved through our reforestation activities and compares the results with the average yearly amount needed by an adult person.

G. arborea is 47% carbon. 3.67 kg CO2 is taken from the atmosphere to produce each kg carbon of wood while 2.67 kg of O2 is released.

O2 consumed per adult - 306kg/year

O2 produced per tree - 45.3kg/year

More information found at the following sources: source 1, source 2 and source 3.

4.0 - Tree Canopy (m2)

The word canopy has a number of different meanings according to the context. In biology, the canopy is the aboveground portion of a plant community or crop, formed by the collection of individual plant crowns. In forest ecology, canopy refers to the upper layer or habitat zone, formed by mature tree crowns and including other biological organisms

Lastly, the term canopy can be referred to the extent of the outer layer of leaves of an individual tree. This document considers the latter definition to perform a calculation on the average horizontal projection of a single tree.

Average Horizontal Projection: 7,6mt x 7,6mt

Very Small Canopy - 150 square feet (approximately 3,5mt x 3,5mt)

Small Canopy - 400 square feet (6mt x 6mt)

Medium Canopy - 900 square feet (9mt x 9mt)

Large Canopy - 1600 square feet (12mt x 12mt)

More information found at the following source: source 1.

Reference calculations and assumptions

Values from the studies are not modified, yet Kijani's growth rates for the G. arborea are found to be higher based on current growth rates for a 2m x 2m spacing compared to the research's 3m x 4m spacing. Kijani's survival rates have been 95%+ for trees over one year, but since we have not completed a year in our Nursery Hub model, we are assuming 90% to of trees that are 1 year old will survive beyond year two.

These data points are an average of the first 6 years of growth for the Gmelina arborea recorded by: "Growth, biomass, carbon storage and nutrient distribution in Gmelina arborea Roxb. stands on red lateritic soils in central India" S.L.Swamyetal. / BioresourceTechnology90(2003)109–126.

Gmelina biomass is 46.66% elemental Carbon per S.L. Swamy and the stoichiometric weight of CO2 is 44 g/mol versus 12 g/mol for C. Therefore (46.66% kg C / kg biomass * (44 g/mol)/(12 g/mol) = 1.71 kg CO2/kg biomass.

Traditional earth kilns have a maximum yield of 6-10% in literature but Kijani has found our species to reach 18% conversion. Most recent experiment yielded 37% charo.

From the Periodic Table of Elements a.44.00 g/mol CO2 / 12.00 g/mol C = 3.67 for CO2 b.O2: 45.3kg =2.67 * (13.2+3.76) based on 32.00g/mol O2 / 12.00 g/mol C = 2.67 for O2

"Production and Regression Models for Biomass and Carbon Captured in Gmelina arborea Roxb. Trees in Short Rotation Coppice Plantations in Costa Rica" Carolina Tenorio , Róger Moya * , Edgar Ortiz-Malavassi and Dagoberto Arias

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