L. David Roper
http://www.roperld.com/personal/roperldavid.htm
7 September, 2017
In my quest to analyze data of global systems that are affected by or affect global warming, I have been looking for data about the deforestation of USA forests to analyze.
The best data I have found are in the following graph:
http://nrs.fs.fed.us/pubs/gtr/gtr_nc241.pdf
I digitized all four curves and added the results to get values for the entire USA:
year |
South |
North |
Pacific |
Rocky Mts |
Total (10^6 acres) |
1630 |
356 |
297 |
242 |
155 |
1050 |
1669 |
356 |
298 |
242 |
155 |
1051 |
1712 |
356 |
296 |
242 |
155 |
1049 |
1733 |
356 |
295 |
242 |
155 |
1048 |
1743 |
356 |
294 |
242 |
155 |
1047 |
1754 |
355 |
293 |
242 |
155 |
1045 |
1765 |
353 |
293 |
242 |
155 |
1043 |
1776 |
353 |
288 |
242 |
155 |
1038 |
1787 |
352 |
287 |
242 |
155 |
1036 |
1797 |
350 |
282 |
242 |
155 |
1029 |
1807 |
348 |
275 |
242 |
155 |
1020 |
1817 |
346 |
267 |
242 |
155 |
1010 |
1828 |
342 |
255 |
242 |
155 |
994 |
1839 |
337 |
241 |
242 |
155 |
974 |
1849 |
331 |
226 |
242 |
155 |
954 |
1860 |
327 |
219 |
242 |
155 |
943 |
1869 |
313 |
204 |
241 |
154 |
912 |
1880 |
305 |
185 |
240 |
153 |
883 |
1890 |
284 |
159 |
239 |
152 |
834 |
1900 |
265 |
149 |
238 |
152 |
804 |
1912 |
244 |
139 |
237 |
151 |
772 |
1923 |
230 |
135 |
238 |
149 |
752 |
1934 |
223 |
153 |
237 |
148 |
761 |
1944 |
229 |
158 |
231 |
142 |
760 |
1954 |
229 |
163 |
231 |
141 |
764 |
1965 |
221 |
163 |
226 |
140 |
750 |
1974 |
214 |
164 |
223 |
141 |
742 |
1983 |
215 |
166 |
222 |
142 |
746 |
2002 |
218 |
167 |
222 |
143 |
751 |
More recent data: 2010: 751.3; 2012: 766.2
I used the hyperbolic tangent function to fit the data. The best fit is:
The fit is , where a = 1043, b = 757.0, t0 = 1869 and w = 42.23 .
Forest area in the United States has stopped the sharp decline that existed for about 100 years. However, recent research indicates that USA forests are slowly continuing to decline area by about 6x106 acres per year.
http://news.mongabay.com/2010/0427-hance_forestloss.html:
http://earthobservatory.nasa.gov/IOTD/view.php?id=44717&src=eorss-iotd:
http://www.nationalatlas.gov/articles/biology/a_forest.html:
From https://www.nifc.gov/fireInfo/fireInfo_stats_totalFires.html:
L. David Roper interdisciplinary studies
L. David Roper, http://www.roperld.com/personal/roperldavid.htm