Ecologists came to the conclusion that forty-year subsidy program for reforestation in Chile was ineffective. One of the obvious failures — in some cases for the establishment of forest plantations, the cost of which was compensated by the government, cut down natural forests. The modeling showed that about five percent are lost for the duration of the programme, forests were cut down because of the subsidies, although the area of plantations would have increased without government intervention. If subsidies were not, the amount of stored carbon would increase and the decrease of biodiversity would be less. According to calculations, published in the journal Nature sustainability, a program of subsidies would be more effective if it had banned the use of under plantation area occupied by natural forests.
To combat the effects of climate change and biodiversity loss, some countries are financing large-scale reforestation projects. Government subsidize the planting of trees to restore the cut forests, to increase the absorption of carbon dioxide and create habitats for other species. However, this often leads to the fact that most are grown commercially viable trees (e.g., fruit), and as a result, instead of natural forests appear monocultural plantations.
One of the largest reforestation projects carried out , the authorities of Chile from 1974 to 2012: the government defended the landing against expropriation and offset usedonmost of the costs. This program as the model used and other countries in South America, however, until now, not been conducted a comprehensive analysis of the impact of subsidies on the restoration of natural forests, the absorption of carbon dioxide and biodiversity. The researchers suspectthat the project could do more harm than good — for example, it is knownthat timber companies cut down natural forests to make their place on the program of subsidies to grow the plantation.
Environmentalists from the U.S. and Chile under the leadership of Robert Heilmayr (Robert Heilmayr), University of California, Santa Barbara explored the satellite land use maps of Chile from 1986 to 2011. With their help, scientists simulated three scenarios: a subsidy program by law, 1974, no subsidies and subsidies that would apply only in areas not covered by natural forests. Used four models: econometric, which determined the profitability of different land-use types in different conditions; model Monte Carlo, which predicted the use of land, depending on three scenarios of subsidy; a model of carbon accounting; a meta-analysis of studies of biodiversity.
Since 1986 more than one million hectares, which was previously covered by natural forests (337 thousand ha), shrubs (515 thousand hectares) and farmland (710 thousand hectares) under forest plantations. According to the econometric model, without subsidies, the area of forest plantations also would increase due to the fact that the cultivation of the plantations is beneficial in itself and would have been only 3.28 percent less. And if the subsidies did not cover the felling of natural forests for plantations, have been able to recover only 13 thousand hectares (about one percent) lower. But 4.7 percent is lost during 40 years of the program, the forests cut down because of subsidies; they also prevented the natural recovery of three thousand hectares of natural forests at the expense of areas covered by shrub or border agricultural land.
In the next stage, the ecologists calculated how much carbon would have stocked forest in the three scenarios. This took into account regional differences in the Central regions of Chile in plantations, even more stored carbon than natural forests, and in other areas the relationship can be reversed. For example, in Waldowski forests contained 146 tons of carbon per hectare, and in the nearby plantations — 37.
Overall, from 1986 to 2011 in Chile, the carbon stock increased by two percent due to the doubling of the area plantations, and despite the decline in natural forest areas by 13 percent. If subsidies were not, have been able to maintain a 0.8 percent increase in the carbon stock, and if subsidies are not concerned employed natural forest areas — ten percent more.
Also, scientists have calculated that the subsidies accelerated decline of biodiversity in Chile due to the expansion of plantations at the expense of natural forests — species diversity of the latter is much higher. According to the calculations of researchers, 3.76 per cent reduction in biodiversity is explained by the subsidies. If natural forests are not cut down for plantations, reducing vodorazdelnaya would be reduced by 78 percent.
As shown in this work, the Chilean model of forest restoration can be improved. And to grow new trees on improved programs around the world — environmentalists found 900 million hectares of land available to plant trees. This forest area will be able to link 205 gigatonnes of carbon.