Interviewer: SHUYI YIN (M.E.D 18′), JANE WENG (M.E.D 18′)
Chadwick Oliver is the Pinchot Professor of Forestry and Environmental Studies, and Director of Yale‘s Global Institute of Sustainable Forestry. His important early works in the book Forest Stand Dynamics which present the understanding of how forest stands develop and can be managed silviculturally. His current interests lie in how to use this understanding to help resolve scientific, technical, environmental, and management issues at the landscape and global levels.
Paprika: Your research has been focused on the understanding of how forests develop and how silviculture can be applied to ecological systems most effectively. In your book Forest Stand Dynamics, you describe the four phases that trees go through in stand development. Could you tell us architecture school students more about it?
Chadwick Oliver: It’s a book on how forests grow. It took a slightly different pathway when I began looking at this subject in the 1970s with my professor here at Yale. Instead of examining the forest as a whole, which was the previous way foresters studied forests, we started looking at the trees as independent growing plants. As trees began growing, they formed patterns which are called an emergent pattern now. Since we concentrate on individual trees, it became interesting. Because the scope of the study expanded a little bit further into not beginning by saying this is the natural forest and this is people, we don’t demarcate that way. Human and nature are not separated entity. They influence each other. Through the emergent properties of the forest and the interactions of individual trees, we are able to come up with a lot better understanding of how the forests grow and behave.
P: Were you looking at the natural forest or commercial forest when you studied the behaviors of trees?
CO: We don’t really separate when studying the behaviors of the trees. A tree, when it grows, it doesn’t have a brain, so it doesn’t know whether it’s in a commercial forest or in a natural forest. It simply responds to certain variables in its environment. We not only look at forests that are not heavily managed by human but also look at those which are managed. We study all of them. Because we don’t demarcate between nature and human. Rather than demarcating the natural forest and the commercial forest with a hard line, we prefer to see the difference as a gradient, from the ones people adjust a little bit all the way to the extremely human adjusted ones. The trees might grow differently, but the fundamental reasons for these differences are not what kind of forests they are in, instead, the reasons might be the spacing among them, or whether the species are genetically modified.
P: What is a stand? And when did this concept come into being?
CO: The stand is a contiguous area of relatively uninformed soils, climate, species distribution and pass history. So that we can treat it as a group. It is an old concept which has been around for over 100 years. But the way in which forest grew within each stand was different earlier than it is now.
P: What do you think caused the difference?
CO:The early concept was that the trees in a forest helped each other. They were like a big family. And the big trees helped the little trees. Then, we found out that it was just not the case. It makes beautiful poetry, but it’s just not very good science. Because the behaviors of the trees relative to each other could be explained much more if we look at them not as they are helping each other. Forests consist of some little trees and some big trees, in different species. (Drawing on paper) Everyone thought this big tree was helping those little trees, but when we looked at the age of them, we discovered that the little trees and the big tree were at the same age. It turned out that if the bigger trees weren’t here, the little trees would have grown taller. We could understand the forest much better by considering trees competing, rather than helping each other. We also have found the same phenomenon occurring everywhere in the world. What’s interesting is that no species wins always. For example, one species might grow very well on the very best soil, but when moved to poor soil, it might get very weak. And the other trees who behave better in the poor soil can stay stronger and win. Therefore, differences in soils, climate, or disturbance determine what kind of species or which trees would win in the competition.
P: What do you think are the goals of managing the forest?
CO:From a scientific point of view, we have to consider that there is no goal. But for the survival of human race, certain things are very necessary, such as clean water, clean air, and biodiversity. One of the things we want to do is to maintain the biodiversity because the forest is a habitat for many species. The biodiversity has long been modified by human, we cannot undo it, but we can just learn how to modify it the right way. Normally we wouldn’t consider touching the old forests, but when we began studying these forests, we realized that disturbances were natural. (Drawing on paper) There are five types of forests, some grow dense and young, others grow larger. Some of these larger forests would develop an understory type or into complex forests. And there is another one called Savanna, where the trees are apart from each other. Young forests can grow towards complex forests, but disturbances can take them back to an open structure, or to the Savanna kind. There are species that are in danger because of a lack of certain structure. If we look at the number of species, most important forests are the open ground, the Savanna, and the Complex.
P: Many of us thought using wood is bad for the environment. There seemed to be the tension between human settlements and forests. However, according to your research, using wood as a building material is actually reducing the carbon footprint of human settlements.And it seems that there might be more trees and forests than we thought before. Can you explain this to us?
CO: Three percent of the dry land surface is covered by cities, and another 11-12% of it is covered by agricultural fields. So we shrunk the forested area here (shrink the diagram). Not only have we shrunk it, but we also have road crossing the forests. So animals have troubles getting from one place to the other. And another thing happened is that we’ve stopped many of the fires and other disturbances. So we don’t have very much of open grounds and Savannas. And we’ve been cutting the complex forests. We are losing these three important structures along with the species that live there. Now the problem is that we are growing much more wood than we are harvesting. So the forests are getting more and more crowded and the structures of forests become more and more toward dense and understory. So through our actions without intention, we are threatening the biodiversity in the forest. Some people would say let’s just leave it alone. But the trouble is that when we leave it alone, we get very big forest fire. We need to actively remove some of the trees to solve the problems mentioned above.
P: Aren’t there a lot of forests taken by farmland? That seems like the cases for example in China.
CO: Actually, the forest land in developing countries is remaining just about stable. The farmland in some countries even gets less and less as the productivity of the farmland increases. In developed countries, we don’t have a reduction in the forest area. Because we are not using very much of wood, the forests become too dense. We have around ⅔ of the forests left. The importance is that, in the remaining forests, we want to maintain the three important structures (Open ground, Savanna, and the Complex).
P Is this how you find the necessity to connect forestry research to architecture?
CO: We will be doing two good things by using wood the right way. If we cut all of the complex forests, it wouldn’t be a good idea because we are losing habitats for different species. The complex forests are great habitats, and it takes too long for them to grow. So instead of trying to grow complex forests and cutting them and growing again, we should just set those areas aside to a certain percentage. If we manage the dense and understory forests, we could cut some trees here and there, and let them go to Openings or Savannas, and grow again and cut again. So that we will always maintain the important structures for biodiversity. If we have some ways of using the wood, then that will pay for our cutting it out of the forest. Right now in the world, 15% of the forests is set aside for protection and the rest of it just used in different ways. If we make wooden buildings out of cross-laminated timbers, we will not only help maintain the biodiversity but also save CO2 from the atmosphere, because we are not burning fossil fuels to make steel and concrete. Thus, it is benefiting both sides. The point is that we have to make sure we manage the forests correctly and cut the right trees.
P: What is the current relationship between the forestry and the architecture fields? Are there a lot of active collaborations already?
CO: In the United States, Scandinavian countries, Russia and Japan, traditional houses were always built out of wood, but not with the big cross-laminated timber. The cross-laminated timber has only been around just for very few years. I’m very excited about how much more is becoming adopted.
P: What is the difference between cross-laminated wood and other types of wood we used before as building material?
CO: Well, I would almost put it into three types of wood. One is the type we build single families houses out of, which is what we call it two by four plywood, that’s kind of traditional. Then the laminated timber or veneer is kind of engineered wood like cross-laminated timber, but because they are cut into very thin pieces and glued. It takes a lot of energy. The nice thing about cross-laminated timber is that it doesn’t take much energy because we don’t cut it and glue it from small pieces. Cross-laminated timbers also have a tremendous amount of strength. Recently, people have been building 18-story high-rise out of those.
P: What is the reason that wood has not been widely used for a long time? Is it because the cross-laminated timber technology wasn’t mature enough?
CO: Yes, it’s a quite new technology. Four years ago, if I googled on cross-laminated timber, I only got three places in the world reporting it. Now you get very many places reporting it. New manufacture plants and new buildings are going up in many places. It’s very exciting.
P: What is the forest management challenge right now?
CO: There are different generations of foresters. We had a generation growing up thinking the important thing was providing enough wood for people. And we need to say don’t just think about the wood, but think about how trees live in the forest. Now the main management challenge is to change the demarcation, the way forester thinks. Besides the challenges with the foresters, we also have many environmental people who grew up with the idea that cutting trees in natural forests is bad. We are trying to change the way of thinking from both sides.
P: What are your current interests and the projects you have been working on?
CO: We are working on a project with the UNDP in Turkish forest service to make the forest management we just talked about completely transparent so that people will trust us since they can monitor the whole process. Through the management model we proposed, we could potentially provide enough employment for people all around the world, which will be a really benefit.
P: What do you think is the role of technology in forestry management?
CO: We develop a system which is a digital model simulating forests grow (Opening desktop). We have this technology where we can take up an area and we can fly over it with a satellite so that we could get an inventory of it. for example, this forest has about 3000 hectares. We can get an image of how the forest looks like. We could look at how forest grow. We’ve just grown it and this is what it looks like in 2065. We can also tell you how the forest will look like if we cut it in a certain way this year. For example, let’s leave about five trees to the acre. And then this is what it looks like right after we have cut it. we plant it afterward, and let the forest grow until 2065. This software can show you how the forest will be like by then.we had a forest that was in the open structure, then it was in a savanna structure, and now it is growing back probably toward a complex structure. And we can keep managing all the forests Until we get a complex structure.
P: Is this based on historical data?
CO: Well, yes and no. we get the inventory, and then satellite stations spend years and thousands of dollars remeasuring trees to get growth models. So we can project how it’s going to look. And then we just have an automated system here. In Europe, they have a satellite that circles the earth about every 11 days and does radar scanning so that you can look at the radar and determine how the forest is like in any places on the Earth so that we know whether we are following our plan. If we put it up online, people can follow us (Google has asked me about it), so that our management method can be more trustworthy. We are using very unnatural scientific tools, like satellites and data to maintain biodiversity in nature, which is important for humans to live.
P: Bringing the traditional building material wood back to our contemporary architectural design arena is very interesting to us.
CO: It’s exciting. I’m glad it’s been thought of that way!