010-2019 MINAE, published in Supplement 40 of La Gaceta of Wednesday, the twentieth of February of two thousand nineteen, in point 2.1, subparagraph g), so that it reads as follows:
- g)The National Forest Financing Fund is instructed to incorporate into the Payment for Environmental Services contracts for the activity of Reforestation and Agroforestry Systems en bloc, the minimum acceptable reference values for making payments.
The minimum reference values (valores de referencia mínimos, VRM) for diameter and total height, required to proceed with the payments for each year, are as follows:
Table 1. Minimum reference values for diameter (DBH) and total height (Htot), expected per year for plantations of fast-growing species (Gmelina arborea, Vochysia guatemalensis, Acacia mangium, others).
| Age (years) | VRM DBH (cm)* | VRM Htot (m)* |
|---|
| 1 | - | 3.69 |
| 2 | 8.14 | 6.85 |
| 3 | 12.08 | 10.26 |
| 4 | 14.28 | 12.39 |
| 5 | 17.69 | 15.08 |
| 6 | 19.08 | 16.74 |
| 7 | 21.11 | 17.42 |
| 8 | 22.12 | 18.02 |
| 9 | 23.02 | 18.54 |
| 10 | 23.83 | 19.01 |
Table 2. Minimum reference values for diameter (DBH) and total height (Htot) expected per year for plantations of medium-growth species (Tectona grandis, Pinus sp, Cordia alliodora, Vochysia ferruginea, Eucalyptus sp, Cedrela odorata, others).
| Age (years) | VRM DBH (cm)* | VRM Htot (m)* |
|---|
| 1 | - | 1.65 |
| 2 | 4.78 | 3.24 |
| 3 | 7.57 | 5.06 |
| 4 | 9.08 | 6.24 |
| 5 | 10.72 | 7.49 |
| 6 | 12.47 | 8.78 |
| 7 | 14.26 | 10.10 |
| 8 | 16.04 | 11.42 |
| 9 | 17.76 | 12.71 |
| 10 | 19.37 | 13.94 |
| 11 | 20.83 | 15.09 |
| 12 | 21.52 | 15.86 |
| 13 | 22.60 | 16.83 |
| 14 | 23.52 | 17.71 |
| 15 | 24.28 | 18.52 |
| 16 | 24.91 | 19.25 |
To calculate the total volume, the following equation must be used:
Where:
Vtot = Total volume per hectare expressed in cubic meters.
л = (pi) is the ratio of the length of a circumference to its diameter in Euclidean geometry.
DBH = Diameter at 1.3 m height expressed in meters.
Htot = Total height expressed in meters.
Fr = Form factor equal to 0.5.
N = Number of trees per hectare.
*The reference values come from data from permanent sampling plots of companies that reforest contributed by the National Forestry Office (Oficina Nacional Forestal, ONF), data from the plots contributed by Forestry Regents and recorded by FONAFIFO, both data sets validated by Dr. Edgar Ortiz Malavassi, Professor at the Technological Institute of Costa Rica.