USA Forests' Deforestation

L. David Roper
http://www.roperld.com/personal/roperldavid.htm
7 September, 2017

U.S. Forests' Data
Fit to data
Conclusion
References
Forest Fires

Introduction

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.

United States Forests' Data

The best data I have found are in the following graph:

http://nrs.fs.fed.us/pubs/gtr/gtr_nc241.pdf

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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

Fit to the Data

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 .

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Conclusion

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.