Forestry & Forest Ecology formula solvers
Canopy Light Extinction (Beer's Law for a Canopy)
Forestry & Forest EcologyLight falls off exponentially as it passes down through leaf layers, exactly as it falls off passing through a coloured solution or a slab of lead. Monsi and Saeki brought the physicists' attenuation law into plant ecology in 1953, and the extinction coefficient k that came with it encodes how the leaves are tilted.
Carbon from Dry Biomass (and CO₂ Equivalent)
Forestry & Forest EcologyRoughly half of oven-dry plant matter is carbon, so a carbon stock is a biomass multiplied by a fraction — 0.47 is the IPCC default. Multiply the carbon by 44/12 to reach the CO₂ that would be released if it all burned, which is the figure carbon markets and inventories trade in.
Fractional Canopy Cover from LAI
Forestry & Forest EcologyThe share of the ground a canopy actually shades, as the complement of what its Beer's law lets through. It approaches 100 % but never reaches it, which is the honest reason a real canopy always has a few sunflecks on the floor.
Leaf Area Index (LAI)
Forestry & Forest EcologyThe total one-sided leaf area a canopy carries, divided by the ground area beneath it. A pure number, and the foundational canopy quantity: light interception, transpiration, rainfall interception and photosynthetic capacity are all read off it before anything else.
Litter Turnover Time and the Steady-State Forest Floor
Forestry & Forest EcologyAt steady state the forest floor stops changing because what falls onto it each year equals what rots off it, and the standing stock divided by the annual litterfall is the mean time a leaf spends lying there. It is the same k as Olson's decay model, measured with a scale and a frame instead of a litterbag: τ = 1/k.
Olson's Single-Exponential Litter Decay
Forestry & Forest EcologyJerry Olson's 1963 model: litter loses a constant PROPORTION of whatever is left in every equal interval, so the mass remaining falls exponentially. One fitted constant k describes a whole litter type, and it is the most-used equation in decomposition ecology despite fitting the late stages of decay badly.
Stand Basal Area per Hectare
Forestry & Forest EcologyAdd up the cross-sections of every stem on a plot, divide by the plot's area, and you have the standard measure of how heavily a site is stocked — the number every thinning prescription, stocking guide and growth model is written against. Reported here in m²/ha, with the ft²/ac equivalent alongside.
Tree Basal Area from DBH
Forestry & Forest EcologyThe cross-sectional area of a stem at breast height, from its diameter. Nothing more than the area of a circle, given a job: it is the currency forestry counts stocking, competition and growth in, because it is the one dimension of a standing tree you can measure accurately with a tape.
Tree Biomass from an Allometric Equation
Forestry & Forest EcologyThe power law every forest carbon inventory rests on: oven-dry biomass as a fitted coefficient times diameter at breast height raised to a fitted exponent. There is no physics in it. It is a regression through trees somebody cut down and weighed, and everything difficult about it follows from that.