[R] HELP OUT

[Eshema Imaledo]

Dear Sir/Ma,
I am a young  forest biometrician that adopted the method that consider how correlation within plot and between stand can be handled.
Actually i am working on modelling height-diameter relationship under different canopy layer using mixed model approach.
METHODOLOGY:
> Height and diameter measurement of tree under different canopy layer was taken at stand level.
>stand attributes such as quadratic mean diameter(Dq),mean height(Hm),dominant height(Ho),dominant diameter(Do),Basal area of the largest tree(BAL) were included in the selected models.
>I considered Dq,Hm,Ho,Do and BAL as the fixed component,and canopy layers as the random component.The canopy layer are tagged suppressed(4),intermediate(3),Co-dominant(2) and dominant(4)
>How do i analyse the fixed and random effect of this models.The models and example of data to be analysed are attached.
I will be grateful for  any suggestions and the command to run this analysis on R.