While partial harvests can appear to be a gentle and light-handed approach to forestry, “selective” harvesting can be extremely destructive and deleterious to long-term sustainable and profitable forest management if the harvests result in high grading. High grading is the practice of removing the highest-value wood from a tract of forest land and leaver less-desirable, sometimes unmarketable wood. The practice greatly degrades the value of the parcel and its subsequent timber production. left unchecked, high grading can ruin the commercial value of forests and necessitate further silvicultural treatment, including clearcutting.
The Long Term Effects of High Grading
Imagine you are on a five day camping trip. At the beginning of the first day, you open up your bag of trail mix. It’s only the first day, so you have to make it last the entire trip. That shouldn’t be a problem–It’s a big bag! You go about enjoying your treat, but you don’t really care for the raisins, so you grab handfuls of the mix and let the raisins sift out of your hand before pulling it out of the bag. Now you have handfuls of M&Ms and peanuts. Yummy. Then day three comes. You’ve only eaten half the bag, but all the M&Ms are gone. It’s now only peanuts and raisins, and it is no longer appetizing to you. Congratulations, you just high graded your trail mix. You were technically sustainable in your consumption of the trail mix, only eating about 20% per day, but by eating the good stuff first, the latter half was useless to you. Your consumption was ultimately inefficient, wasteful, and sub-optimal.
The same process can happen in forestry. Trees come in all species, shapes, and sizes, and naturally some trees are more valuable than others. It can be tempting to maximize the profits of a harvest by taking out all the “good stuff” and leaving the rest, but the result is a forest full of low quality, undesirable wood, and any subsequent growth the residual stems put on will be likewise low quality and undesirable. When it does come time to harvest the stand in the future, you will find the forest you are left with is much like the bag of raisins from the camping example. At best, you will be stuck with a low rate of return from harvesting poor quality wood. At worst, you will be stuck with a deeply unhealthy forest of unmerchantable, worthless stems that will be nearly impossible to harvest and sell. Your forest will be effectively ruined without further silvicultural treatment to alleviate the condition.
Remember, you do not have a tremendous amount of control over how fast your forest grows. This is mostly determined by your region and the DNA of the trees. However, you do have control over the value of the individual trees. A forest may only grow .5 cords per acre per year, but will that .5 cords be worth $30 a ton or $100 a ton? The answer can be dependent on forest management and whether previous harvests high graded the stand. Clearly, the consequences of high grading are dire, and serious care must be taken to ensure the value of the forest is maintained or improved over time.
How to Avoid High Grading
Avoiding high grading requires a commitment to forest management and the enhancement or preservation of the many values the land offers. Such a commitment necessitates sound silvicultural understanding and a conscientious effort, but the first step is determining what exactly is valuable in your forest. Value is of course relative to your objectives. If you wish to manage for periodic, profitable harvests, your main concern will be the overall value and marketability of your timber. If, however, you are managing a small woodlot for firewood, the biggest concern will be species. Ask yourself what you are managing for and tailor harvests around maintaining or enhancing those values.
In general, regardless of your specific objectives, there are two main characteristics that need to be carefully maintained or improved to prevent high grading. These two characteristics are species and quality.
To avoid high grading species, release or retain vigorous individuals of valuable species. Even if you take all the mature individuals, are there younger stems that can be left? Are there patches of regeneration that can be released from the canopy’s shade so they can grow? If all individuals of a given species are mature, and there is no desirable regeneration in the understory, perhaps the stand is suitable for a shelterwood treatment to regenerate the stand and promote new, valuable growth.
Just as important as promoting valuable species is taking care to harvest less desirable species. Without this crucial step, even careful efforts to maintain species composition will fail as the undesirable stems become a greater percentage of the stand. Thus, finding a market or use for these trees is paramount. In cases where wood can absolutely not be used or sold, it can still be worthwhile to cut the unmarketable stems and leave them on the forest floor. Though it may seem wasteful, such practices give room for better species to grow and improve the land over time.
To avoid high grading quality, one should follow much the same standards. High quality straight and vigorous stems that will continue to grow and put on value should be retained or released. low quality stems should be harvested to give room for higher quality or more vigorous stems to grow. Eventually, of course, all high-quality stems will need to be harvested, as this is the entire point of growing them in the first place. The key is to think down the road to the next harvest. Ask yourself: Will these stems be more or less valuable next time this stand is harvested? If they will be more valuable in the future, it is a good idea to retain them. If they have likely maxed out their growth and value production and now run the risk of mortality, it is time to harvest these stems and allow younger stems to flourish.
What to Do if Your Forest Was High Graded
Sometimes we inherit mistakes from the previous landowner or maybe our parents or grandparents who managed the land before us. Maybe land was badly high graded and is now of little value for timber production. As unfortunate as it is, there are options. However, due to the nuance involved in such decisions, it is wise to contact a local forester to discuss your situation and maybe organize a visit to the property. They can recommend a course of action based on your specific situation.
Don’t Steal From the Future
The goal of forest management should be to maintain or enhance the value of a forest over time. High grading is antithetical to this principle. While it may be tempting to maximize short term profits, like picking out the M&Ms out of a bag of trail mix, high grading hurts the landowner most of all. It merely steals from the future of the forest. If you are planning a harvest or actively manage your forest, take care to ensure your prescriptions align with sound silviculture and avoid these sub-optimal and wasteful outcomes.