My intent is to model plant growth with a generalised linear mixed model. Let's say I sampled growth of 10 plants each on 10 plots in five different (non-consecutive) years. In order to find out which factors influence growth I have several variables which characterise the plots (e. g. elevation, soil) and several variables which characterise the conditions in the year in which sampling took place (e. g. maximum temperature, length of vegetation period). My model now looks like this:
Growth ~ elevation + soil + maximum temperature + length of vegetation period + (1|Plant ID)
Plant ID is a unique ID across all plot (i. e. A_1, A_2, .., B_2, B_2, ...).
Would I still have to include plot and year of sampling as (nested?) random effects, even though they are (indirectly, i. e. as their characteristics) included as fixed effects?