The direction of slope and elevation can be taken into account in carbon sequestration storage models by considering the topography of the land and its ability to store and sequester carbon. For example, areas of steep slopes may be less suitable for carbon storage due to higher erosion and leaching rates, while flat or low-slope areas may be more suitable for carbon storage due to their stability and ability to store more carbon over time. Additionally, higher elevation areas may be more prone to colder temperatures and lower carbon storage rates, while lower elevation areas may be more conducive to carbon storage due to warmer temperatures and higher storage rates.
Slope and height are important factors indeed, but a least as important is the orientation of a slope eg. the azimuth angle with respect to the South. A Northern oriented slope will have a different species composition and irradiation regime as opposed to a Southern oriented slope.
Also mind that absolute humidity will change with height, since it depends on temperature! At a certain height one reaches the condensation point and hence water vapor will turn into liquid water which can be taken up by roots and even epiphytes. Not to be neglected indeed in view of carbon sequestration!
You provided an acceptable explanation. In my opinion, these factors are very important in pastures. For this reason, I try not to neglect them in modeling...