I'm doing a timeline where people colonize Iceland, talking probably Classical or Ancient, maybe the Celts do it. I've tried to study much of Iceland and it's climate, but it looks like inner Iceland looks inhospitable, with all of the glaciers, tundra, and volcanoes. One of the things that got me thinking was land reclamation, I don't really know much about it, but I've been wondering if Pre-Modern Land reclamation can be plausible, specifically on Iceland. I've also been wondering if it brings any benefits such as agriculture and such to make conditions in the coast more livable since going into the highlands is near impossible. Another thing that I was thinking for the Celts living there was crannogs, if the Celts used them, could they be used as a mean to reclaim land from seas?
Correct me if Im wrong on any of this, but I was thinking of this in this timeline and was wondering the options.
Iceland's desolation is mostly manmade.
Iceland is a volcanic island situated on a hotspot on the North America-Eurasia boundary; it's made up of mostly the material produced by its stratovolcanoes...and much of that, is ash. Eons upon eons of tiny, white, fluffy ash comprised much of Iceland's soils, which in turn provided the nutrients for plants leading all the way up to trees which later came to dominate.
Enter Norse settlers, who saw this lush abundance and a-went to choppin'. Unfortunately once Iceland's inland regions got to the point where they supported vast forests, the root systems of those trees and the plants that depended on them were the primary means of keeping that soil intact. Once those were gone, it was up to the wind and storms to blow all that soil away like a ripe dandelion. Luckily the Icelanders eventually started to realize the fragility of their ecosystem and adopted practices that tried to preserve both it and them. Today there are restoration projects in place but I don't remember how intensive they are.
Your Celtic settlers might 'repeat' this mistake if their population density is high enough. Even if they're the stereotypical 'tree cult' at first a culture can always change. All depends on how you write it.
But there are historical examples of preindustrial land reclamation, that is beyond irrigation projects which were nearly widespread. The two that immediately come to the top of my head are the Aztec chinampa plots and the Irish
Aran Islands, whose inhabitants used sand and seaweed in stone-bordered plots to turn rocky islands into fertile soil capable of supporting crops and grazing.
Speaking of the Aran Islands, check out
this post I and a few others made about terraforming the Kerguelen Islands a while back.