A Case for Winter Weather: Timber Harvest

As a child, the prospect of playing in the snow with my family was always an exciting one – especially when it was accompanied by free-flowing hot chocolate. As an adult, the prospect of shoveling my driveway and cleaning snow off of my car in an effort to navigate a slick highway is not necessarily as exciting (even if the hot chocolate is still free-flowing). Yet, as someone who cares personally and professionally about our forests, I know that cold, frozen, and moderately snowy winters are important not only to the natural processes in forests but also to the best possible management of them. This is particularly true where timber harvesting is concerned.

Conducting a commercial timber harvest in Pennsylvania requires the utilization of large equipment: skidders, dozers, feller bunchers, forwarders, and so on. This equipment is integral to felling trees, transporting them through the forest to log landings, and getting them off the landing and onto log trucks or into chippers. In conducting a harvest, they will have to repeatedly navigate in and out of the forest, across streams or roads, and into stands on the same trails. As you can imagine, activity at this scale can and will cause disturbance to soil and water. In Pennsylvania, there are regulations in place designed to minimize the potential negative impacts of that disturbance. A requirement for all timber harvest operations, as dictated by said regulations, are Erosion and Sedimentation (E and S) Control Plans. These are site-specific plans, written by a forester or logger, that describe how an operation will implement best management practices (BMPs) to protect the soil and water resources present. BMPs are defined activities (like never skidding logs directly through stream channels or developing water diversion structures to minimize runoff on trails and haul roads) that are to be undertaken throughout the sale process in an effort to mitigate changes to soil and water that can lead to, that’s right, erosion, sedimentation, and their myriad of ecological consequences. Implied in this is the value of winter timber harvests.

When the ground is frozen, and especially frozen and covered in snowpack, harvest can occur with minimum damage and/or contact to the soil. In these conditions, soil is not deeply saturated and muddy. Therefore, the movement of equipment is less likely to result in large ruts and intense soil compaction, which can cause damage to tree roots and alter soil structure, changing the productivity, water and nutrient holding capacity, and overall condition of the site. The absence of rutting, compaction, and other soil disturbance decreases the likelihood and/or load of sediments displaced and deposited in waterways. Winter harvesting is also beneficial for the next trees to come. In the winter months, trees typically remain in dormancy, storing their water and nutrients in their roots rather than moving them throughout their stem. Even after a tree is removed, this root system and that vital energy within it remains. In the spring, the seedlings that might sprout from that root system will be better prepared to grow because of those remaining nutrients. For foresters and loggers, the freeze and snow of winter is a welcomed safeguard against damage accrued in a harvest and a mechanism for supporting the health and productivity of the next forest. But the weather of today – and tomorrow – will provide fewer and fewer opportunities for winter harvest.

When you reflect on the weather you experienced as a child or when your parents share stories from their youth, a common sentiment is that winter weather used to much harsher and summers cooler. And those reflections are not unfounded – while weather and temperature vary year-to-year, the average annual temperature and precipitation rates have changed and will continue to change over the next century. In the past 20 years alone, the state’s average annual temperature has increased by 1.2°F and it is projected to have increased by almost 6°F at the end of the next 20 years. Across those next 20 years, the average number of days above 50°F is projected to increase by 50%. Regarding precipitation, Pennsylvania has seen an increase of almost 4.6 inches (11%) annually since 2000 and is projected to experience an 8% increase by 2040. The winter and spring months will experience the greatest increases in precipitation – but in the form of rain rather than snow. In summation, our winter seasons (and really the remainder of the year), on average, are and will continue to be warmer and wetter than before. This will reduce the time that the ground will spend frozen. A timber harvest operation will not be able to reliably enter a site and begin a job if the ground is frozen one day and then soft and inundated with ice/snow melt the very next. So not only do these changes in winter weather limit the opportunities available to forester/loggers to conduct harvest with minimal risk to soil and water, but they add an element of inefficiency and uncertainty to a job – impacting the prosperity, plans, and budget of everyone from the logger to the forester to the landowner. This is all not to mention the damage that these freeze-thaw cycles and increases in winter temperature can have on trees left behind in the woods (i.e., frost heaving, frost cracking, frost injury).

I love warmth and sunshine and mutter under my breath while shoveling my sidewalk just as much as the next person – but I deeply value the resources in our forests, and, when they are actively managed, it is important that that management is sustainable, efficient, and occurs with minimal disturbance to the surrounding ecosystem. To achieve that, we need an awareness of our climatic future in the Commonwealth, as well as an element of stability in our average weather patterns and a good, solid stretch of bitter cold. And, yes, even snow.

The Pennsylvania Forest Stewardship Program provides publications on a variety of topics related to woodland management. For a list of publications, call 800-235-9473 (toll free), send an email to PrivateForests@psu.edu, or write to Forest Stewardship Program, The Pennsylvania State University, 416 Forest Resources Building, University Park, PA 16802. The Pennsylvania DCNR Bureau of Forestry, USDA Forest Service, Penn State Extension, and the Center for Private Forests at Penn State, in Partnership through Penn State’s Department of Ecosystem Science and Management, sponsor the Forest Stewardship Program in Pennsylvania. 

Written by Abby Jamison, Forest Stewardship Program Associate, Center for Private Forests at Penn State