Interpreted ET M+in 2006

150000 and 1100000 topographical map

forest type map

data of Class II forest inventory in 2007 in Pingtonghe watershed were applicated.Firstly

the satellite images was interpreted and the vector format was converted to grid format

then grade assessment of each grid was carried out by using element model on the basis of selecting stand structure factor

production capacity factor and function factor.The results showed that:(1)The area of firewood forest in this area was in the ascendant (32785.4 hm2

or occupying 42.45% of the total area);it was followed by water conservation forest and soil and water conservation forest

the former occupied 23.88% (18 441.86 hm2) and the latter accounted f or 15.60% ( 12 047.44 hm2);while economic forest only occupied 5.46% (4217.3 hm2).(2)On the whole

the quality of protection forest was poor:the middle grade occupied 62.75%

the next was fine grade(21.21%)

the poor grade made up 13.96%;however

the superior grade only accounted for 1.24%.