A forest is more than a trees collection...
The increase in the concentration of carbon dioxide (CO2) in the atmosphere since the beginning of the industrial age has caused an increase in the temperature average of the order of 0.6 ºC, which has induced changes in the processes climatic, with negative consequences both biological and economic and social (UNEP, 2003). It is accepted that almost 20% of CO2 emissions come from the elimination and degradation of forest ecosystems, from so that the interruption of deforestation and the restoration of forest cover through reforestation and sustainable forest management natural, involves recapturing atmospheric CO2 and mitigating global warming.
How to reduce Co2 atmospheric concentration and how to calculate trees capture carbon?
There are two ways of decreasing CO2 concentrations in the atmosphere. The first is to take an active role in reducing our CO2 emissions. (which comes from burning fossil fuels for energy, agriculture, and transportation, land-use changes like deforestation, and more). The second is to capture carbon by sucking it back out of the atmosphere. We need to focus on both solutions if we want to see a real change.
Native forest restoration is the most efficient and cost-effective carbon capture solution available. In order to accurately assess the current situation — and measure our progress — we need to be able to quantify the amount of CO2 sequestered in existing and future planted forests.
How do trees capture carbon?
Much of the carbon stored in a forest is located in its trees. Trees need water, light, and oxygen to function and grow. Photosynthesis is the process by which trees use light to turn CO2 and water (H2O) into carbohydrates, or sugar, and then release oxygen (O2) back into the atmosphere.
Trees then use carbohydrates as food to fuel growth and other functions, just as we do as humans. The bigger the tree, the more carbon it stores. Reestablishing a thriving forest ecosystem, full of diverse species native to the area, captures the most carbon of any forest restoration method.
Trees aren’t the carbon sink. The forest is.
A common objection to tree planting as a carbon capture solution is that the carbon storage is only temporary: supposedly, when trees die, they release their carbon back into the atmosphere. And if it’s temporary, why do it?
As it turns out, this is only (somewhat) true for individual trees, but not for forests.
First, trees don’t release all of their carbon back into the atmosphere. A large portion cycles into the soil as the tree decomposes. Roughly speaking, this is how carbon moves from the air into the soil.
But even more important is that a tree is not an individual, it is part of a system. During a single tree’s lifetime, it seeds many children. By the time that tree dies, there could be many younger ones growing to take its place. The decomposing tree also feeds the soil, making way for other understory growth and eventually an entire food chain.
Together, this ongoing growth takes up all of the CO2 released by the dead parent, and often much more. Decomposition is a slow process, which means that most of the CO2 is either cycled into the soil, or taken up by new plants. All of this new growth contains carbon. Over decades, and even centuries, forests grow denser and continue to multiply their carbon sequestration capacity.
A forest is more than a trees collection…
Forests are complex ecosystems, anchored by specific tree species suited to their biomes, and filled out by a web of life dependent on those trees—from bacteria to fungi, insects, other plants, and animals. While it’s tempting to accelerate carbon drawdown by planting swaths of the fastest-growing tree species, plantation-style stands hold far less carbon than forests composed of diverse native species.
A tree growing in its native habitat supports potentially 10 times as many species as an invasive one. This is because native trees have co-evolved symbiotic relationships with all the other organisms in their habitats over millions of years—relationships that invasive species don’t have. The forest anchored by native tree species can absorb many times more carbon than plantations of non-native species.
It is the whole system — not just the anchor trees — that is the carbon sink. So while trees alone don’t necessarily offer a durable carbon drawdown solution, forests do.
Individual plants live and die, but a forest expands and deepens as a carbon sink. Native anchor tree species are the foundation that make the rest of a forest possible. Planting the right trees in the right place is the path to forest restoration, which is the true carbon capture solution.
How do we measure the weight, or biomass, of a tree?
To measure how much carbon is stored in a tree, we first need to figure out what its weight, or biomass, is. Biomass is the organic material of living organisms, and about half of it is carbon (C). When it comes to trees, we usually refer to their dry biomass, after the water has evaporated.
The only way to accurately measure a tree’s biomass is to cut it down, dry it, put it on a scale, and record the total weight of its parts — its trunk, branches, leaves, and roots.
In non-destructive methods, an estimate of the biomass is made per volume calculations from direct measurements in the field, where the planting density (number of trees per hect.area), the diameters and height of the trees are measured and and also the base area . You can also calculate biomass and later carbon by mean of models based on regression analysis between variables collected in the field or in forest inventories and their corresponding biomass dependent variables.
To lead the Carbon Neutrality initiative, EARTH University implements. a quantification methodology that allowed to determine, for a hand, CO 2 emissions and, on the other hand, carbon stocks in the Vegetation (including natural forest, plantations and agricultural systems). TO Some of the methodological aspects are detailed below. Carbon in the aerial biomass of natural forests (primary and secondary) and forest plantations. To determine the carbon (C) accumulated in the biomass of the areas of natural forests (primary and secondary) and forest plantations, first calculated. the timber volume. For this, the basal area is determined in each of the sample units. The basal area (AB) is the sum of the cross-sectional areas (.area of the trunk at 1.30 m height) of all the trees with a diameter greater than 10 cm existing in one hectare (and expressed in m 2 /ha).
for 1 ha
AB = [ (mean DCH)2. x 0.7854 ] (m2/tree) x N (tree/ha)
Then its average height is determined. The product of AB multiplied by the height and by a coefficient of form (ratio. between the real volume and the apparent volume of a tree) is the timber volume or volume of the stems.
Vol = AB x H x 0.5
Then, from the volume, the carbon content is determined, which is the product of the volume multiplied by the dry matter content (% DM, is considered. 50%) and by the content of C in the MS (% C = 50% accepted the IPCC). Amount of C = Vol. x 0.5 x 0.5 t or this quantity of C the Biomass Extension Factor (BEF) is applied equal to 1.6 considering an additional 60% content in branches and foliage (in the literature this factor is mentioned with a range between 60% and 90%) and the total figure is multiplied by the respective area of each of the units.
Characterization of the sampling area:
Sampling is a procedure by which a part of the population is studied population called sample, with the aim of inferring with respect to the entire population. In our case the population is a plantation or a natural forest. The site within the area with plantation or natural forest to be sampled must be representative of the stand that we are interested in calculating the catch of carbon.
Selection of trees for sampling:
For biomass sampling, they will be established in each study site as a minimum of three circular plots of 100 m 2 (with a radius of 5.64 m, established with a rope). Within each plot, the number of existing trees with a diameter at breast height, measured at 1.30 m from the ground (DBH), equal to or greater than 10 cm, to calculate the density expressed in trees per hectare (arb/ha) . For example, since the plot is of 100 m 2 , each individual counted within it represents 100 trees per hectare (1 ha = 10,000 m 2 ). In each tree within the sample the diameter is measured (with a diametric tape, a caliper or the circumference of the stem or trunk at a height of 1.30 m and is divided by π = 3.1416).
For the purposes of this exercise, only the aboveground biomass (biomass above ground) of each tree is divided into 3 components:
1) Biomass of the total stem.
2) Biomass of branches.
3) Biomass of leaves.
For other Carbon Inventories, data is also taken for the determination of the biomass of the other components or strata, such as the necromass (dead biomass), understory and leaf litter. for this three samples of biomass per stratum will be considered, which are taken also to the laboratory to dry in the oven and determine the content of dry material.
BIOMASS EXPANSION OR EXTENSION FACTOR
The Biomass Expansion Factor (BEF) is a coefficient that allows add to the biomass of the stems, obtained from the volume inventoried in the field, the biomass corresponding to the branches, leaves and roots, that is, the BEF expands the dry weight of the calculated stock volume to include the non-timber components of the tree or forest.
Before applying these BEF, the timber volume (m 3 ) must be converted to dry weight (ton), multiplying by a conversion factor known as basic density of wood (D) in (t/m 3 ). BEF’s have no dimension, since they convert between units of weight.
For example, if in our sampling we have a density of 350 arb/ha, an average DBH of 22 cm and an average height of 18 m, we have that:
• AB = (0.22 m) 2 x 0.7854 x 350 arb/ha = 13.3 m 2 /ha
• Vol = 13.3 m 2 /ha x 18 mx 0.5 = 119.7 m 3 /ha
• Biomass = 119.7 m 3 /ha x 0.5 t/m 3 = 59.9 ton/ha
If to that amount of biomass a:
• BEF = 1.3 : Total biomass = 59.9 ton/ha x1.3 = 77.9 ton/ha
• BEF = 1.5 : Total biomass = 59.9 ton/ha x1.5 = 89.9 ton/ha
The BEF will vary depending on the characteristics and dimensions of the trees evaluated. Trees with smaller diameters and highly branched present older BEF In the IPCC guidelines (IPCC, 2006), the expression Biomass Conversion and Expansion Factors, which combine conversion and expansion.
Their dimension is (t/m 3 ) and they are transformed by a single multiplication stocks volume stocks like the one we do in our exercise (m 3 ) directly into a.area biomass (t). BCEF are more appropriate and are those presented in the tables of the IPCC guidelines.
They can be applied directly to forest inventory data based on volume and operational records, without having to resort to basic densities of wood (D). They give better results when derived locally and when they are based directly on venous volume. Mathematically, the BCEF and BEF are related by the formula:
BCEF = BEF x D
Where BEF: Biomass expansion factor and D: wood density
How to measure the height of trees
Sampling Strategy A: For each species, two trees in each crown class are measured to get an idea of the overall variation.
Sampling Strategy B: Sample plots are established, and all trees in a plot are measured.
Tree height measure:
A method based on the similarity of triangles, where proportionality exists between their sides.
1) A stick is taken which is equal in length to the distance between the eye and the observer’s fist.
2) It approaches or moves away from the tree until the visual that goes from the eye to the upper end of the stick and reaches the apex of the tree to measure and the visual that goes from the eye to the lower end of the stick and reaches the base of the tree to measure coincide.
3) At that time there is a resemblance of triangles where the height of the tree is at the length of the rod as the distance to the tree is at the distance from the eye to the rod. Since the distance from the eye to the rod is equal to the length of the rod, then the distance from the tree is the height of the tree.