PRACTICAL ARBORICULTURE 157 
WHY HAVE FORESTS DISAPPEARED IN COLORADO AND 
OTHER SEMI-ARID STATES? 
Neither science nor physics, as construed by modern philosophy, explains 
the contrary conditions existing in the Orient to-day with that of B. C. 1000, 
or even A. D. 100. No more do they interpret the causes of America’s arid 
belt or its encroachment upon the fertile country. 
Meteorology details the thermal changes of the atmosphere and their in- 
fluences upon air currents, moisture and precipitation, but meteorology does 
not explain why a country which once produced such massive trees should 
now be so barren, or why a province that once had abundant rains should be 
so arid. 
Mathematics has no data upon which to predict a theorem and is thus 
unable to enlighten us when this change occurred. 
Geology makes mention of fossils and petrifactions which are found in 
various parts of the earth, and in different geological periods. It presumes 
IN PETRIFIED FORESTS 
that indefinite ages have elapsed since certain changes occurred, but geology 
does not explain why these trees once thrived in a region which will produce 
them no more. 
Botany gives the distribution of plants upon the globe, relates with minute- 
ness those plants which exist in an arid climate, yet botany has never at- 
tempted to explain why the sequoia grows upon the highest Sierras and 
nowhere else in the world, while undoubtedly it did thrive in the Rocky 
Mountains in former times. 
There is no rule of science which can satisfactorily account for the 
change which has taken place in climate since these trees grew. Nor yet 
how long since the change occurred. 
Speculation fails to elucidate the problem and only tells us that the 
Sierra Nevada Mountains squeeze the moisture out of the passing clouds 
before they reach the desert. Was it always so? Was this natural law in 
force when the mighty cedars and sequoias were growing in the Rocky Moun- 
tains? 
