The tropical trees planted by Planeta Verde Reforestación S.A. are generally tolerant of poor soils, but do need a warm climate and lots of rain. Our location in the Orinoco River basin, along the Rio el Bita in the departamento of Vichada, Colombia, meets those criteria, with average temperatures around 25° C (77° F) and annual rainfall around 2,268 mm (89"). There is a distinct dry season (mid-December to mid-April) and a wet season from late April through to early December.
The process begins with the purchase of certified seeds, which have better genetics and better germination rates. In the case of some native tree species there are no commercial sources, so we have instituted our own seed collection program in the rainforest. In the tree nursery we use sprouting tables, and seedlings that successfully germinate are then placed in planting bags. The size of the planting bag depends on the species, its rooting habits and the size required before planting in the field.
Our tree nursery is split in two. We operate a large tree nursery for introduced species, and a second tree nursery for native tree species and fruit trees. The only trees we outsource are cashew trees, which come from a specialized nursery in Puerto Carreño. We have an irrigation system to mist the seedlings in the tree nursery, and in the case of some species also set up sun screens. However, we try to emulate field conditions as much as possible for heartier seedlings.
Soil preparation occurs while the seedlings are in the nursery. We plough to a depth of 75 cm (30"), which allows the majority of tropical trees to set deep roots quickly. Depending on the species we may also lime the soil at this time, to balance pH, which can be acidic in tropical soils. Fertilization generally occurs at the time of planting. We use a special forestry fertilizer that consists mainly of elements needed for rapid tree growth, such as phosphorus, potasium, nitrogen, magnesium, boron etc.. The trees obtain the balance of their nutritional requirements from the sun, the air and the rain.
Planting season is in the middle of the wet season, generally from early July through to mid-August. Species that are more rain sensitive, like Anacardium occidentale (cashew trees) are planted as late as September. Tropical trees are planted in a grid. Fast growing carbon sequestration species like Acacia mangium and Eucalyptus pellita are planted 2.80 m X 2.80 m (9' x 9') apart, while fruit trees may be 10 m (30') apart and cashews as much as 12 m' (36') apart. Introduced species may average 1,250 trees per hectare (2.47 acres) after planting, while there may be as few as 100 fruit trees (mango, tamarind) per hectare.
After planting there are two more annual fertilizations that occur. Trees planted for lumber are pruned to eliminate duplicate trunks within their first year, and small branches are pruned from the trunk after the trees initial growth spurt, usually in the 4th year of growth, to eliminate unsightly knots in the wood. Good forestry management also dictates that ample fire breaks are placed around and throughout all cultivations. Most tropical tree species also act as natural fire breaks by their third year. Constant monitoring by our forestry engineers and an annual visit by a tree pathologist are part of our process.