How managing low-quality wood (also known as low-use wood) for bioenergy can encourage sustainable forest management

管理低质木材（也称低用木材）用于生物能源如何鼓励可持续森林管理

A  A tree's 'value' depends on several factors including its species, size, form, condition, quality, function, and accessibility, and depends on the management goals for a given forest. The same tree can be valued very differently by each person who looks at it. A large, straight black cherry tree has high value as timber to be cut into logs or made into furniture, but for a landowner more interested in wildlife habitat, the real value of that stem (or trunk) may be the food it provides to animals. Likewise, if the tree suffers from black knot disease, its value for timber decreases, but to a woodworker interested in making bowls, it brings an opportunity for a unique and beautiful piece of art.

A 一棵树的“价值”取决于几个因素，包括它的种类、大小、形态、条件、质量、功能和可及性，还取决于给定森林的管理目标。同一棵树，不同的人对它的评价可能截然不同。一棵又大又直的黑樱桃树有很高的木材价值，可以砍成圆木或制成家具，但对于对野生动物栖息地更感兴趣的土地所有者来说，这棵树茎(或树干)的真正价值可能是它为动物提供的食物。同样，如果这棵树患了黑结病，它的木材价值就会下降，但对于一个对制作碗感兴趣的木工来说，它带来了一个制作独特而美丽的艺术品的机会。

B  In the past, Pennsylvania landowners were solely interested in the value of their trees as high-quality timber. The norm was to remove the stems of highest quality and leave behind poorly formed trees that were not as well suited to the site where they grew. This practice, called 'high-grading', has left a legacy of 'low-use wood' in the forests. Some people even call these 'junk trees', and they are abundant in Pennsylvania. These trees have lower economic value for traditional timber markets, compete for growth with higher-value trees, shade out desirable regeneration and decrease the health of a stand* leaving it more vulnerable to poor weather and disease. Management that specifically targets low-use wood can help landowners manage these forest health issues, and wood energy markets help promote this.

B 在过去，宾夕法尼亚州的土地所有者只对他们的树木作为高质量木材的价值感兴趣。通常的做法是砍掉质量最高的树干，留下不太适合生长地点的粗劣树木。这种被称为“高分级”的做法在森林中留下了“低利用率木材”的遗产。有些人甚至称这些树为“垃圾树”，它们在宾夕法尼亚州大量存在。这些树木在传统木材市场上的经济价值较低，与高价值的树木竞争生长，遮蔽了理想的再生，降低了林分的健康，使其更容易受到恶劣天气和疾病的影响。专门针对低利用率木材的管理可以帮助土地所有者管理这些森林健康问题，而木材能源市场有助于促进这一点。

C  Wood energy markets can accept less expensive wood material of lower quality than would be suitable for traditional timber markets. Most wood used for energy in Pennsylvania is used to produce heat or electricity through combustion. Many schools and hospitals use wood boiler systems to heat and power their facilities, many homes are primarily heated with wood, and some coal plants incorporate wood into their coal streams to produce electricity. Wood can also be gasified for electrical generation and can even be made into liquid fuels like ethanol and gasoline for lorries and cars. All these products are made primarily from low-use wood. Several tree- and plant-cutting approaches, which could greatly improve the long-term quality of a forest, focus strongly or solely on the use of wood for those markets.* Stand – An area covered with trees that have common features (e.g. size)

C  木材能源市场可以接受比传统木材市场更便宜、质量更低的木材材料。在宾夕法尼亚州，大多数用于能源的木材被用来通过燃烧产生热量或电力。许多学校和医院使用木质锅炉系统为其设施供暖和供电，许多家庭主要用木材供暖，一些煤电厂将木材纳入煤流中发电。木材也可以气化用于发电，甚至可以制成液体燃料，如卡车和汽车的乙醇和汽油。所有这些产品主要由低使用量的木材制成。有几种砍伐树木和植物的办法可以大大改善森林的长期质量，但这些办法的重点是或仅仅是在这些市场上使用木材。*树林-覆盖有相同特征(例如大小)的树木的区域

D  One such approach is called a Timber Stand Improvement (TSI) Cut. In a TSI Cut, really poor-quality tree and plant material is cut down to allow more space, light, and other resources to the highest-valued stems that remain. Removing invasive plants might be another primary goal of a TSI Cut. The stems that are left behind might then grow in size and develop more foliage and larger crowns or tops that produce more coverage for wildlife; they have a better chance to regenerate in a less crowded environment. TSI Cuts can be tailored to one farmer's specific management goals for his or her land.

D 其中一种方法被称为林木改良(TSI)砍伐。在TSI切割中，质量很差的树木和植物材料被砍掉，以便为剩余的最有价值的茎留出更多的空间、光线和其他资源。清除入侵植物可能是TSI切割的另一个主要目标。留下的茎可能会变大，长出更多的叶子和更大的冠或顶，为野生动物提供更多的覆盖;在一个不那么拥挤的环境中，它们有更好的机会再生。TSI削减可以根据一个农民对他或她的土地的具体管理目标进行调整。

E  Another approach that might yield a high amount of low-use wood is a Salvage Cut. With the many pests and pathogens visiting forests including hemlock wooly adelgid, Asian longhorned beetle, emerald ash borer, and gypsy moth, to name just a few, it is important to remember that those working in the forests can help ease these issues through cutting procedures. These types of cut reduce the number of sick trees and seek to manage the future spread of a pest problem. They leave vigorous trees that have stayed healthy enough to survive the outbreak.

E  另一种可能产生大量低利用率木材的方法是回收木材。随着许多害虫和病原体访问森林，包括铁杉，亚洲长角甲虫，祖母绿灰螟和舞毒蛾，仅举几例，重要的是要记住，那些在森林里工作的人可以通过砍伐程序帮助缓解这些问题。这些类型的砍伐减少了病树的数量，并试图控制害虫问题的未来蔓延。他们留下了强壮的树木，这些树木保持了足够的健康，在疫情爆发中幸存下来。

F  A Shelterwood Cut, which only takes place in a mature forest that has already been thinned several times, involves removing all the mature trees when other seedlings have become established. This then allows the forester to decide which tree species are regenerated. It leaves a young forest where all trees are at a similar point in their growth. It can also be used to develop a two-tier forest so that there are two harvests and the money that comes in is spread out over a decade or more.

F  谢尔特伍德采伐只发生在已经砍伐过几次的成熟森林中，涉及到当其他幼苗生长时，将所有成熟的树木移走。这样，林务员就可以决定哪些树种可以再生。它留下了一片年轻的森林，在那里所有的树木都处于相似的生长阶段。它也可以用来发展两层森林，这样就有两次收获，而投入的资金将在十年或更长时间内分散。

G  Thinnings and dense and dead wood removal for fire prevention also center on the production of low-use wood. However, it is important to remember that some retention of what many would classify as low-use wood is very important. The tops of trees that have been cut down should be left on the site so that their nutrients cycle back into the soil. In addition, trees with many cavities are extremely important habitats for insect predators like woodpeckers, bats and small mammals. They help control problem insects and increase the health and resilience of the forest. It is also important to remember that not all small trees are low-use. For example, many species like hawthorn provide food for wildlife. Finally, rare species of trees in a forest should also stay behind as they add to its structural diversity.

G   为防火而进行的间伐和清除密木和枯木的工作也以生产低用木材为中心。不过，重要的是要记住，保留一些被许多人归类为低用木材的木材是非常重要的。被砍伐树木的顶部应留在原地，使其养分循环回土壤中。此外，有许多蛀洞的树木是啄木鸟、蝙蝠和小型哺乳动物等昆虫捕食者极为重要的栖息地。它们有助于控制问题昆虫，增强森林的健康和恢复力。同样重要的是要记住，并不是所有的小树都是低利用率的。例如，山楂等许多树种都能为野生动物提供食物。最后，森林中的稀有树种也应该保留下来，因为它们增加了森林结构的多样性。