Eyes on Earth Episode 21 - Forests of Ghana

STEVE YOUNG:

Hello, everyone. Welcome to this episode of Eyes on Earth. We are a podcast that focuses on our ever-changing planet and on the people here at EROS and across the world who use remote sensing to monitor and study the well-being of earth. I am your host, Steve Young. Today's guest is Francis Dwomoh. He is a remote sensing research scientist working with ASRC Federal, a contractor to the USGS EROS. Francisí focus here at the Center is on Land Change Monitoring, Assessment, and Projection, a project we call LCMAP. But today we are interested in talking about his previous work for the Forestry Research Institute in his native Ghana. Francis relied a lot on Landsat images for that work, looking at how forests in his homeland and the surrounding subregion of western Africa have changed under the influence of climate, land use, wildfires and more. Welcome, Francis. 

FRANCIS DWOMOH: 

Thank you, Steve. 

YOUNG:

Francis, as I understand it, your homeland of Ghana historically was largely forested and now people say that maybe 20% of those historical forests remain. What happened to them?

DWOMOH:

Historically weíve had a third of the country, thatís approximately like 8 million hectares of the country was originally forested, even way back into the 1900s. But now, we are down close to like 2 million. So, you are right to say that. And these kind of changes were mainly driven by population growth and economic factors. In that, a lot of people who rely on forest resources for various uses. But then the government also relies on a lot of the revenue from timber exports. But then, back to the agriculture, weíve had very rapid population growth. And when you have that, what it means is that you have to grow more food to feed the people and that has led to more clearing of the forests, you know, for agricultural expansion. One of the major economic avenues for Ghana as a country is also cocoa. Which is the raw material for making chocolate around the world. A lot of people are into that. And traditionally people have to pull down the forests in order to plant cocoa.

YOUNG:

Is the electrical grid such that people rely more on woody biomass for energy in West Africa?

DWOMOH: 

In big cities you have most people using liquified petroleum gas. And very few people use electricity for heating and cooking. One, because it is not really available all the time and it is also expensive. And, so in these cities, people still rely on wood fuel. When you go more to the rural areas, where we have most of the people, itís mainly wood fuel. Either in the form of firewood or charcoal. So, that has also been a significant contribution to the decline in our forest resources.

YOUNG:

You talked a little bit about how the growth in agriculture and the expansion of agriculture means forests get cut down so that there can be more agriculture. Youíve also indicated I think in different times that such things as climate, logging, are all having an impact on forests there. How so? 

DWOMOH:

Ideally a tropical forest like what we have in Ghana retains more moisture because the canopy is closed. So it is usually wetter and is difficult to burn it. Now, when you start removing a lot of the trees, you are reducing the canopy, so you have more light, sunlight, coming in. You remove more trees, the tree debris that are left get dried up. They are fuels that are being accumulated. Now, we have a lot of agriculture around this forest and fire is the main tool that people use to clear their lands. Fire can easily escape from theses agricultural fields. Sometimes people who use fire for hunting animals. These fires enter the forests, and it easily burns because the canopy is opened and more sunlight drying. And of course when there is so much opened, wind is able to quickly spread through and is able to burn these forests. Now from the work we are doing and that has been done in other parts of the world, what happens is, that the first time when the forest is being burned, itís a little bit harder. But, once it burns, then subsequently it is easy to burn. So for instance, the first time maybe it would take a big drought for the fire to start. But when the first fire burns, what happens? It kills more trees. Those trees eventually become wood fuel. So that the next time another fire comes, there is a little fuel already to burn and then the impact becomes bigger. When you are into that kind of situation, it is very hard for the forest to come back because any time you burn, you are increasing the quantity of fuel that you have within the forest. And now, itís even more of a challenge because with climate change and climate variability, we are having more droughts. And when you have more droughts with high temperatures, they help to speed up these fires and make the fires even more severe and create more negative impact within the forests.

YOUNG: 

So, you do all this work using remote sensing, do you then turn what you find out over to decision makers in your country? Do they buy in to what youíre providing them from a remote sensing standpoint?

DWOMOH:

We are scientists but we try to bring the decision makers in as much as we can. So, for some of my work, at various places, we have been able to show how vulnerable the forests have become. And, if you look at the region, there are projections that there are going to be more droughts and in most places temperatures also are going to rise. So, it tells the managers of these resources the threats they are facing, how they are evolving, and how they can plan to manage the resources. Quite recently, with my work in University of Oklahoma, we developed a forest monitoring system entirely based on Landsat data. So, we take thousands of the Landsat data and we are able to track forest changes, that is able to provide estimates of the changes that are occurring within the forests every single year. Now, that is quite important because Ghana has signed onto the United Nations climate initiatives. And with that, you should be able to account for changes in your forests and how that translates into carbon, that threatens the stability of our climate. But more importantly, they are able to also target where the deforestations are occurring, where the fires is occurring so that they can manage to reduce these losses and also enhance the ability of the forests to recover from these disturbances.

YOUNG: 

How important are forests culturally in Ghana? Is there something culturally significant about forests? 

DWOMOH: 

Thatís an interesting question. Yes, forest land and forest resources play very significant for within the cultural and the spiritual life of the people. In certain localities, there are certain rituals and festivities that are only performed inside the forests. And some of those rituals, you only do them with certain kind of either tree species or animal species that are only found in certain kinds of forests. There are places where like in very important people in the community like the chiefs, the kings and the royals, when they are dead, there are particular places where they are buried. So, in some communities you go, all the forests around the place is gone but you see what we call sacred groves. Because that is where the chiefs and the kings, they are buried. A lot of our water, and major rivers and lakes, they have their sources from these forests. And even within the spiritual, apart from water being, you know, linked to our lives, they also have cultural significance to the people. Even the language that we speak, we use a lot of idioms, proverbs and all that. We talk about folk tales and stories and we talk about heroes and all that, you know the monster in the forests, the fairies in the forests, the dwarfs and all that. They are all linked to the forests. So, when we are losing these forests, it means a lot to the people culturally.

YOUNG: 

How do you use remote sensing to track all of this?

DWOMOH: 

We are talking about looking at the forests, the location of where things are happening, when it happens. And it is only remote sensing technology that can be able to do that, to be able to track where and when things happen and what happened and what has been the consequences of when those events happened. Without remote sensing we would not be talking about it. It is the only technology that gives verifiable information and especially for larger areas like we are talking about. The whole forests zone of Ghana, it is impossible to do for us when you are in it and like that.

YOUNG:

And Landsat, has that been an important part of the whole remote sensing arsenal you use, and if so, how?

DWOMOH:

Yes, Landsat has been the launchpad for most of this research. Landsat has the capability to show us what is happening within the landscape. So, we are able to track where this is happening on the landscape. But more importantly, we can go back far into history. Landsat has been around since 1972. So we can track these changes at a scale that is relevant to the people as well as provide a historical context to these changes. But more importantly, when you are working in developing countries, Landsat, which it is provided by the USGS free of charge anywhere in the world, it is significant because you donít have to bother about, ìWhat is the budget line for buying data?î Now, it is freely available, the entire archive. And that has been a very rich resource for doing all of this. Without that, we would not be talking about any of this research. It would have been impossible to do that.

YOUNG:

So, are the forests recovering?

DOWMOH:

There are mixed responses. There are few places where the forests are able to come back upon disturbance. But largely, we have locations that are losing their ability to recover especially if we look in the northern portion of, and even to the eastern portion of the forest zone of Ghana. Because most of these areas have been heavily logged already and theyíve had fires that keep repeating. So, the forests donít get enough time to recover upon disturbance because we have multiple fires, you know, successfully over years and when you have droughts, it makes things complicated for the forests to recover. 

YOUNG: 

So are you optimistic about the ability of Ghana and west Africa to successfully regrow their forests in the future?

DWOMOH: 

That is I wish we can do that to recover these forests that have been lost over the years. But, what I see is that the challenge is even more daunting now. Because now there are other drivers that we can face more complicated. Now there is climate change, more frequent droughts and higher temperatures. That makes things more complicated. We would need more efforts and much more resources than before to be able to recover this forests. So, it is a possibility, but it demands far more effort than we have been doing over the years.

YOUNG:

Weíve been talking to Francis Dwomoh, a remote sensing research scientist at EROS who in previous work has used Landsat remote sensing to look at the important issues of forest health and degradation in west Africa including his Ghana homeland. Fascinating conversation, Francis, thanks for joining us.

DWOMOH: 

Thank you, Steve.

YOUNG: 

We hope you come back for the next episode of Eyes on Earth. This podcast is a product of the US Geological Survey, Department of the Interior. Thanks for joining us.