Rainforest logging Rates

The degradation of tropical rain forests is a relatively recent phenomenon that has significant ramifications on the future of life as we know it on planet Earth. Rain forests provide many important natural ecosystem services that are essential to our survival: nutrient cycling, production of oxygen and circulation of atmospheric gases, control of soil erosion, amelioration of global climate change, home to a huge genetic library, source of medicines and food, productivity, and conservation of fresh water.

In order to assess the future conservation of tropical rain forests, we need to quantify their rate of degradation. Many estimates exist throughout current literature, web sites, and news articles. As part of an exercise for our Conservation Biology – rain forest cases studies class in fall 2003, New College students each brought to class a rate of rain forest degradation, as quoted from a specific albeit current news source. The results are tabulated below, but a few considerations require mention.

Several short-comings in the estimates of rain forest degradation require consideration in the evaluation of our data.

Satellite imagery is often used to estimate losses of rain forest. However, satellite imagery does not always discern between plantation and rain forest canopies, or measure selective logging. In addition, it is not clear how satellite imagery discriminates between regenerating and old growth forest, which have obviously great differences in their ability to provide ecosystem services as listed above.
Visual estimates of rain forest losses measure only the loss of canopy cover. There are many other important factors to consider: reduction in mammal populations from the hunting pressure of logging crews, changes in soil compaction and erosion, reduction in populations of birds and insects which are not measurable by satellite imagery or simple sampling techniques, and possible losses of indigenous people and cultural attributes.
Data that is published may not be current, and often does not cite the dates of data collection. Information may be ten years old, and obviously would not be useful; but unless the source clearly cites their time of data collection, it is not possible to get current rates.
Many rates utilize different measurements, ranging from acreage to percentages to time-based losses. It is difficult to extrapolate and create a global understanding of rain forest loss with these different measures.
Most data do not explain how they calculated their data, which is essential in order to assess their reliability.

In summary, it is almost impossible to ascertain the rates of rain forest destruction, except to recognize that published measurements are likely to be under-estimates, due to lack of sophisticated and up-to-date technology suitable to calculate accurate figures. In our class, you will see below that nearly each student found a slightly different rate, and in some cases, the discrepancies were fairly significant!

Conversion Factors

1 hectare is 0.4047 acres
1 kilometer² is 247 acres
1 acre is 4047 meters²
1 mile² is 640 acres
1 football field is 3500 meters²

3600 seconds in an hour
86,400 seconds in a day
315,360,000 seconds in a year

One purpose of this table is to present the diversity of figures quoted for rainforest destruction. However, precisely because such figures are so varied, it is difficult to compare them in a table. Rates may be quoted for a particular span of time (1980 - 1990), including extrapolation into the future, or for a particular geographical area (Brazil), or for a particular method of destruction (logging, burning). The numbers presented below are for global rates, and are presented with a link to their original contexts.

Obviously there is some rounding error when converting between different measurements of space and time.

Methods used to determine these rates vary. Common methods are aerial imagry, logging corporate records, and on-the-ground research.

Rate from text	Rate standardized	Source
1.5 acres/sec	5400 acres/hr	Rainforest Facts
West Africa is expected to lose 70% and East Africa 95% of remaining forest cover by 2040.		Africa Extinct
240 mi²/day, or 6417 acres/hr, or 107 acres/min, or 1.78 acres/sec	6417 acres/hr	Rainforest Biodiversity Scale of Destruction. Rainforest.net, part of LoveEarth.net
78 million acres/yr, or 214,000 acres/day, or 149 acres/min, or 2.4 acres/sec	8940 acres/hr	Rainforest Action Network
70,000 - 170,000 km²/yr	1973 - 4793 acres/hr	Global Forest Watch
51 million acres/yr	5822 acres/hr	OS Earth
86,000 hectares/day, or 2 football fields/sec, or 31 million acres/yr	3539 acres/hr	RainForest Destruction
78 million acres/year, or 200,000+ acres/day (burned), or 150 acres/min, or 1.5 acres/sec	8904 acrse/hr, or 5400 acres/hr	RainTree
40 - 50 million acres/yr	4566 - 5707 acres/hr	Tropical Hardwoods
1.5 acres/sec	5400 acres/hr	Rain-Tree
2.4 acres/sec, or 2 football fields/sec, or 149 acres/min, or 60 hectares/min, or 214,000 acres/day, or 86,000 hectares/day, or 78 million acres/yr, or 31 million hectares/yr	8640 acres/hr	Rainforest Action Network
53,000 miles²/year during the 1980s	3872 acres/hr during the 1980s	Mangrove Forests
2 million hectares/yr, or 20,000 km/yr, or 7 football fields/min	563 acres/hr	News Article
“Tropical deforestation probably exceeds 130,000 km²/yr.”	3665 acres/hr	World Resources Institute
Detailed by region....		Tropical Deforestation Rates