I recently posted about the bleak situation with Quercus petraea silviculture in the south of Vinnitska Oblast. Now I'll give a bit of better news, about efforts to develop natural regeneration techniques in Quercus robur forests in the central part of the oblast. This is the work of Evgeniia Krementska at the National Agricultural University, who is leading a great effort by the forestry faculty to diversify the range of silvicultural options available to Ukrainian foresters. All forest harvests in Ukraine must be identifiable as one of a short list of "approved" harvest types listed in the Forest Code. For obvious reasons, this limits creativity and experimentation. But recently a new type was added: rubka pereformiruvannye, which translates like "reformation harvest". This broad category allows for a variety of treatments that aim to develop desirable structural or compositional characteristics in even-aged stands. Dr. Kremenetska has been establishing experiments in Vinnitska Oblast to demonstrate what this might mean in practice. The best examples are on Tulchinske Forest Management Unit.
In Tulchyn, it is often possible to find good cover of oak seedlings in open areas such as roads and clearings. But a dense midstory of hornbeam often shades them out in the forest. The goal of "reformation harvesting" here is to begin developing advance regeneration of oak as the first step towards creating an uneven-aged stand. This very much resembles the first stage of an oak shelterwood: remove the midstory of shade-tolerants and thin the oak canopy. But in theory the next harvests will start trending more towards selection. Some proportion of the canopy cohort will be retained (they talk about a 200 year rotation for these trees, and hopefully some will be permanently retained), while good patches of advance regeneration will be released with gaps ("windows").
We saw an interesting array of stands where this treatment is taking place. A 70 year old stand where oak and hornbeam were both in the upper canopy, and the latter made up at least 40% of the stand. A really beautiful 100+ year old stand of oak sawtimber with full canopy cover, no hornbeam midstory, and a nice cover of first-year oak seedlings. A 2-age stand with a dominant cohort of 200 year old oaks and a younger oak-hornbeam cohort. In all of these stands high-quality oaks have been selected for retention, while low-grade oak and most of the hornbeam are slated for cutting. It will be very interesting in the next few years to see if advance oak regeneration was successfully released (or established in those places where it is currently shaded out).
Would these treatments actually get used outside of the experimental context? I think they are attractive to foresters whose management units contain a high proportion of "protective forests." In this forest category clearcutting is prohibited, which eliminates the primary method of regeneration here: clearcut-plant. Usually protective forests are managed under a "sanitary selection harvest" regime, in which low-grade trees are gradually culled out in a series of light cuts. This makes for lovely forests, but is not very economical and usually makes no provision for oak regeneration. I think some foresters are beginning to think seriously about real regeneration methods when clearcutting is not available. But I doubt "reformation harvesting" would be much used in the exploitation forest category.
However, we also saw a 3 ha clearcut that was nicely stocked with natural oak regeneration one year after harvest. It seems that this good result could perhaps be replicated if clearcuts were targeted for good acorn years. But the foresters told me that not all stands have sufficient acorn production to achieve such seedling stocking, even in a good acorn year. I suspect this might have to do with crown size, as many stands are very high-density and thus have poorly formed oak crowns.
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