Estimating aboveground carbon stock in forests: Allometric models

Following on from the last blog post, this post will look at another method for measuring aboveground biomass in forests is through the use of allometric models which relate tree dimensions to biomass. This is a good time to discuss this approach, since I’ve spent the past few days comparing allometric models used in two different regional carbon assessments of cocoa farms in Indonesia. Continue reading “Estimating aboveground carbon stock in forests: Allometric models”

Estimating aboveground carbon stock in forests: Biome approach

The aim of this post is to introduce the various methods that have evolved to measure forest carbon stocks and focus on one of the most commonly used high level methods. Subsequent posts will focus on other methods.

Importance of measurement

Forests are of global importance because of their biodiversity and the carbon they sequester. A reservoir or system which has the capacity to accumulate or release carbon is known as a “pool” (FAO, 2016). In the context of forests it refers to the amount of carbon stored in the world’s forest ecosystem, mainly in living biomass and soil, but to a lesser extent also in dead wood and litter. Continue reading “Estimating aboveground carbon stock in forests: Biome approach”

Challenges of remote sensing for mapping plantations

The past week I was helping to compile information and guidance for the Terra-I team to allow them to start mapping the cocoa farms from the polygons they have been given. One of the biggest challenges they will face is distinguishing tree plantations from other vegetation such as secondary forests with a high degree of accuracy. This was backed up by my review of the available literature on this topic on Tuesday.

Spectral confusion (reflectance from vegetation) with native vegetation is a well-known challenge in agroforestry and tree crop systems, particularly in mapping cocoa, shade coffee, oil palm, and evergreen rubber tree plantations. Tree crops are grown using full sun or low shade methods are less likely to be misclassified than when they are grown in densely-shaded agroforest.

Cocoa cultivation systems (source: Jacobi et al., 2013) Continue reading “Challenges of remote sensing for mapping plantations”

Update from the CIAT office

 

Starting to feel like I’m settling into the CIAT office and Hanoi life, now that I have a better idea of what I’ll be working on and where I’ll be staying for the three months. The apartment is a twenty-minute drive from the office, shorter than many of my previous commutes so I’m enjoying that while it lasts. Hanoi in rush hour can be unpredictable like in any city, but despite the heavy traffic during these times it seems traffic rarely comes to a complete standstill (even if it seems like it should!) and miraculously I haven’t been overly late anywhere…yet!

Below is a picture of the front of the building that the CIAT offices are in. CIAT occupy the first, second and ninth floors. There are other agricultural research institutes in the same building, including the International Rice Research Institute.

There are glasshouses on the grounds and although I haven’t been able to identify what is being grown in them, just outside I did notice some mango trees with some decent looking mangoes. Continue reading “Update from the CIAT office”

Terra-I and land-use change detection

Terra-I detects and monitors land cover change resulting from human activities. It was developed in cooperation with CIAT to provide decision-makers and national and local authorities near real time updates of vegetation loss and deforestation.

Terra-I will be a powerful tool for this research project. My ability to estimate the carbon impact at a national level is largely dependent on the Terra-I team being able to locate and estimate the sizes of cocoa plantations. The exercise will require a visual inspection of satellite imagery to confirm what a typical cocoa farm signature should look like. This information will then be able to be fed back into the system in order to replicate on a large scale.

Below is a short time-lapse video of Terra-I detecting land-use change and deforestation (shown in red) in the Amazon.

Climate change projections for cocoa growing regions

My first week in CIAT started with a meeting to discuss aspects of my project with those who are currently involved with cocoa research in Indonesia. It was interesting to see how my research will fit in with other ongoing or completed studies within CIAT. There are other research projects looking at cocoa in Indonesia at regional scales. For my project I will be working to produce a national level assessment of carbon stocks and carbon footprint of cocoa, bringing together all this regional data.

Now is a good time to offer a comment on climate change impacts on cocoa in Indonesia. Over the next century, South East Asia is predicted to experience increased temperatures, increased variability and intensity of rainfall in particular at higher altitudes, and increased risks of high intensity and frequent extreme weather events such as cyclones and droughts (IPCC, 2014). Climate change is already having an impact on cocoa crop yields in Indonesia (Witjaksono, 2016). Continue reading “Climate change projections for cocoa growing regions”

Above-ground carbon stocks on cocoa farms

The first draft of the literature review has been submitted and I depart for Hanoi tomorrow. Since the last post I have been starting to look at carbon stocks and flows on cocoa farms and the following are some key points from what I have been reading.

Carbon stocks on-farm contribute to cocoa farming’s potential for mitigation of greenhouse gas emissions. In order to assess the carbon sequestration and mitigation potential, the carbon stock on farm must be estimated. The carbon stock of the farm is the total carbon stored in the system, including in the cocoa trees, shade trees, soil organic carbon (SOC) and soil litter. SOC is normally the largest contributor to the total carbon stock. In Sulawesi for example, a study found that SOC contributed 55% to the total carbon stock, followed by 22% from shade trees, 12% from cacao trees, 8% from roots, and 8% from soil litter (1), see figure below. Continue reading “Above-ground carbon stocks on cocoa farms”

First blog post – Cocoa production systems

Planning is well underway for my departure to Hanoi next week. I anticipate the change of scenery and new faces will help kick off the next phase of my research project which is a three-month placement in the Vietnam CIAT office.

My literature review research this last week has been focused on understanding what the various cocoa production systems are and why they’re used. Cocoa trees have historically been grown by smallholders within native tropical forests and as such they have a reputation as being a ‘shade-loving’ tree. Every cocoa production system offers different levels of shade to the cocoa trees. The choice of system may be constrained by a number of physical, economic or cultural factors such as climate or yield requirements. Continue reading “First blog post – Cocoa production systems”