Interesting paper on the origin of vegetation in NW Scotland from
the Holocene to present. Not only an area of often complex geology, but also geomorphology, both having an impact on soil development and type, hence influencing vegetational types. Also since the Holocene the climate has undergone some fairly radical shifts of varying intensity and duration. Between the influence of geology, geomorphology, climate, herbivores and humans it rather calls into question the whole concept of climatic climax vegetation, as this is dependant upon periods of stability. Also using such tools as palynology to determine past vegetational patterns only has an assumed accuracy-it may well be frequently erroneous. Peat bogs and sediments providing the pollen are not ubiquitous and what is preserved may be due to vagaries of wind, and pollen morphology may well influence the aerodynamic behaviour and hence distribution. The science of constructing past patterns of vegetation has more than a few gaps   preventing too many assertive statements to be made.
It is a lot like carbon dating- there are a lot of variables to be thrown in the mix to obtain accuracy and the learning curve is probably not yet completed.


http://www.tandfonline.com/doi/full/10.1080/17550870802260624?scroll=top&needAccess=true

https://en.wikipedia.org/wiki/List_of_periods_and_events_in_climate_history