Most people think that to experience rainforest you need to travel to Latin America, Central Africa, or parts of Asia. Well, if you want to see tropical rainforest, that’s certainly true! But there’s another, much rarer, type: temperate rainforest.
In addition to having originally been far more limited in global extent (only roughly 10% of the land area of tropical rainforest), its location in temperate zones has always made the land more attractive for agriculture, and therefore subject to much more drastic reduction due to both clearance and grazing pressure. However, examples of temperate rainforest do still survive in several parts of the world where suitable conditions (principally high levels of humidity in the form of rain, drizzle, mist, fog, etc.) occur, as, for example, the Knysna-Tsitsikamma forests of South Africa, the coastal forests of British Columbia in Canada, and the Valdivian forests of Chile. (Click on https://en.wikipedia.org/wiki/Temperate_rainforest for more information on definitions and global distribution.)
South West Ireland’s position means its climate is largely conditioned by the Atlantic, and in particular by the Gulf Stream, which brings a continual supply of warm waters from southern latitudes. The resulting very mild and wet (hyper-oceanic) climate creates the perfect conditions for temperate rainforest, which once clothed practically the entire landscape. However, over millennia almost all of the original forest was either cleared or died out through overgrazing, leaving only small semi-natural remnants hanging on here and there. One such remnant, Beara Rainforest on the panoramic Beara Peninsula in West Cork, has been painstakingly restored over the course of almost a decade, a process that is still in course.
The close proximity of the Atlantic also means very violent storms periodically batter the forest, which – contrary to what one might expect – brings great benefits in ecological terms. Windthrow and other damage to the trees help create the disturbed conditions that contribute to an extraordinarily dynamic and rich ecosystem, with high levels of structural diversity and rapid change (succession).
Another aspect is that the trees growing here are not just native: perhaps equally importantly, they are wild. That is, rather than having been planted – as is often at least partially the case in other native woods – they are entirely self-seeded, with a local genetic lineage that in all probability extends back over several thousand years, almost to the end of the last Ice Age. The difference is far from abstract: while planted oaks, for example, are notable for their uniformity, by contrast wild oaks (and other tree species) vary enormously between individuals in every possible way, such as overall shape, leaf colour, resistence to disease, etc., creating a habitat that is much more diverse and, hence, biologically ‘useful’ to the myriad other members of the woodland ecosystem.