Do you have field data to accuracy assessment?

Pre-processing and methods done correctly?

In my opinion, it is not necessary that the LAI has a positive correlation with biomass.

This can be influenced by PFTs and plant types.

Hi

First, deforestation doesn't mean that vegatation cover has been completely removed and we now have a bare soil. Deferestation in tropical forest is generally followed by an increase in vegeation activity of plants that are on the ground. So it can be replace by agricultural activities. In case of shallow, regeneration can take place particularly during 20 years.

Second, you shoul;ld really understand what each vegetation indices measures. NDVI and SAVI measure the intensity of vegetation activity, but LAI measure the surface of soil cover by photosynthetically active leaves. They don't measure the same phenomenon. A negative value of NDVI of SAVI doesn't necessarely mean a reduction of biomass on the ground, but a reduction in the vegetation activity maybe due to harvesting, defoliation or plant stress.

Finally, keep in mind that reletion between NDVI and LAI is not linear. many studies have shown it. you should be really carreful when using NDVI to measure deforestation because it;s affected by many factors as weather and climate, soil wetness, vegetation phenology, etc. So your analysis should make sure that situations between years are identical to avoid mistake in interpretation

Thanks

Thank you Guys !

See: Article On the Relation between NDVI, Fractional Vegetation Cover, a...