Oak silviculture in the forest-steppe

For the past couple of days I have been visiting a forest management unit in Chechelnik, Vinnitsya Oblast. This is the "forest-steppe" region- a mixture of wide open chernozem fields and oak-ash forests.  I've been here getting acquainted with the management unit and planning a little botanical expedition in the spring with a colleague from the National Botanical Garden.

I've had a short but fascinating introduction to forestry in this region. It is quite far to the south (near the Moldovan border), and almost in the true steppe zone, where forests are extremely scarce. Natural forests are dominated by Quercus robur and it's less common cousin Quercus petraea, with a sizable component of Fraxinus excelsior, Carpinus betulus, Tilia cordata, Acer platanoides, Acer pseudoplatanus, and Ulmus carpinofolia. There is also a species of wild cherry and "bereka", a rare Sorbus. Moisture is limiting here so the forests are on the xeric side. Typical structure might be oak and ash as dominants, with a midstory of hornbeam, bereka and linden and advance regen of maple, ash and hornbeam. 

Silviculture in this region leans heavily towards artificial regeneration. Seed is collected locally and sown in nurseries around the management unit. Rows are heavily scarified in clearcut areas and either acorns or oak seedlings are planted at quite close spacing. I think the rows are about eight feet apart and within the rows seedlings are 2-3 feet apart. The foresters very frequently enter these young stands to do cleaning and liberation treatments. I think four or five of these pre-commercial treatments is not unusual, followed still by early-commercial thinnings for firewood. (Can these treatments pay for themselves? I'm dubious). Often these plantations are mixed - every fourth row will be maple, linden, ash, spruce, walnut or cherry. 

The management unit was hit hard by an ice storm in 2002. Damage was quite severe, and a large proportion of the trees here have damaged crowns with lots of water sprouts. As a result, many "sanitary clearcuts" have been carried out to salvage heavily damaged stands. However, a large proportion of the management unit is classified as "botanical reserve" (the mixture of northern forest and southern steppe species is quite unique), where clearcutting is prohibited. So here they have been carrying out a series of extremely light "sanitary selection" harvests. These target trees with broken crowns, otherwise unhealthy trees and snags. The volume removed seems very low to me - I would guess that less than 5% is removed in any given harvest. From a silvicultural perspective, it is great to be able to enter these stands so frequently and lightly. But again I have to wonder- can such silviculture pay for itself? Is this management regime self-sustaining, or subsidized by the State Forestry Committee? 

These sanitary selection harvests have some downsides, too. They are not effective at regenerating oak - the gaps created are extremely small and are quickly occupied by advance regeneration of ash, maple and hornbeam. In general, the goal in these forests is to maintain mature crown cover (as is mandated by law), so regeneration is of secondary concern. From an ecological perspective, the constant "cleaning" of these forests is quite severe. They are almost literally without snags and coarse woody material - this is obsessively collected for firewood. Even cavity trees are extremely scarce- I saw one nice ash cavity tree, and the forester I was working with grumbled "why didn't they cut that? Sloppy work..." A few times I broached the subject of whether leaving some snags, downed logs and wildlife trees would be appropriate in an ecological reserve. The reaction was not positive! The foresters here love order and cleanliness, and that means that deadwood is not tolerated. 

Happily, they are beginning to experiment with group selection in protective forests. I saw one really nice mature oak stand where 2-3 tree gaps were cut. (Interestingly, they call gaps "windows"). The natural oak regeneration was beautiful - see the photo above. The foresters seemed quite enthusiastic about this and told me that they plan to try this method in other protective forests in the management unit. But I need to put this in perspective: for every couple hectares where they are trying out group selection, there are probably 50 hectares of intensive clearcut-scarify-plant. The movement towards natural regeneration is very tentative, despite lots of research and support from Kyiv. Ukrainian foresters just love planting trees - it is a major part of their professional image and they regard it as "correct" silviculture.