Planting trees in bogs conundrum

Biogeochemistry

We live in interesting times where anything can be planted anywhere at any time. We have become quite good at it. So if for example, we wanted to grow cabbage on the road tarmac, we have the know-how and technology. If we wanted to have an orange grove in the North Pole, we could. The data on plant life globally that we hold cannot be underestimated. For example, have you ever wondered why the bananas we get in supermarkets are all the same? It does not matter what time of year. It does not matter whether it is Tesco or Supervalu. It’s all the same. The question is why and how.

Bog restoration through agroforestry in these interesting times, however, poses many challenges and insurmountable barriers. The ongoing research outputs from all over the world of course help. Here in Ireland, we have many such research bodies, such as TEAGASC. A lot of focus is quite rightly on commercialisation, costs, risks and benefits at a macro level. For a micro-scale research we are undertaking at Boleysillagh Farm, we have a little bit more freedom and manoeuvrability. The detailed data, such as the genetic make-up and ancestry of each and every cultivar of fruits, nuts and other vegetation, are openly available. The ongoing research on peatland restoration and development is also available even from as far afield as Indonesia. All one needs is the internet. We live in interesting times indeed.

For the restoration of peatlands, in summary, we know that the water table of the bogs must first be raised. This takes quite a while with a lot of trial and error because it is site-specific. We need to determine the main source of the water, whether rain or groundwater or both. We need to artificially construct berms and swales to prevent surface erosion and run-offs, and block or fill the drains. We of course, also need to ensure that the surrounding farms and lands are not adversely affected by our reclamation works, which means agreements with the neighbours. Some areas of the bogs may well be impossible to restore, so that must also be tackled. Some damage, especially in cut-away bogs, may have deep fissures that need to be filled. Once all of that has been undertaken, we must ultimately make sure that the re-wetting keeps the water within an inch of the surface throughout the year. This means monitoring and dealing with drought periods when rainfall is scarce. I have outlined the basic chemistry of this in a separate chapter but I thought it best to repeat it here in context. The goal is to ensure that the bogs will recover over time so that carbon sequestration starts at the earliest possible time. That may mean artificially introducing sphagnum moss at some point in this process. In respect of chemistry, we want the bogs to hold carbon dioxide CO2 and minimise methane CH4 output.

For agroforestry, i.e. trees and plants whether ‘agro’ or ‘forest’, different factors come into play. In our temperate climate, specific to Ireland, with specific geology at play depending on where your bogs may be, the solutions by necessity are site specific. Some fundamentals are the same. Most plants cannot survive being waterlogged throughout the year. But bogs are waterlogged throughout the year. Logic, therefore dictates that we cannot have trees and plants in the bogs. Oh well.

Carbon, nitrogen and phosphorous cycles

Then, there is the chemistry. We know all about NPK. Plants needs NPK in various forms and ratios. They also need micro-nutrients and require the environment to be conducive to producing food with consistent quality and quantity. They also need hands-on management, especially of fruit bushes and trees. If you have ever tried working and even picking fruits and berries in an uneven, overgrown, thorny landscape full of trip and fall hazards, ankle deep in bog mud, you will know what I mean. Yet, bogs are in the most hostile environment. Here at Boleysillagh Farm, wind and gusts can reach 70+ kph almost monthly throughout the year, causing damage. We are at least 100 metres above sea level, and not much shelter exists in any direction. Plus, peatlands by design are required to be nutrient-poor. Thus phosphorous (P) and Potassium (K) are only present in minute amounts and concentrations. Nitrogen (N) (for proteins and DNA in plants) is present, but in the form of ammonia NH4. Coupled with the fact that most plants are not able to handle acidic and anoxic conditions, and a limited presence of microbes, bacteria and fungi, there is some truth in the logic of not having trees in peatlands. Oppositely, to amend the bogs so that plants can thrive in such an environment invariably means destruction of the bogs.

Despite such sage advice, suppose we do plant trees in the bogs, keeping the raised top layer oxic, where the roots have a small chance of keeping dryer and in turn be able to take up some nutrients. What happens then, and what is it that we need to do to keep the balance between the requirements for bog restoration and the requirements for agroforestry? Can we bridge this opposing conundrum via the middle path? What are the challenges that we face? Is there a possibility of overcoming some of them? In peatlands generally, there is a phenomenon called redox gradient operating with the top layer being oxic, the middle layer being suboxic and the bottom anoxic. In planting trees, how the oxic layer can be managed and maintained so that the aerobic bacteria can thrive and support plants without causing detrimental effects on the other two layers becomes vital. So what are the acceptable trade-offs, such as growth vs productivity? How long and how far do we go? That indeed is the million-dollar question that we have been attempting to get data on at Boleysillagh Farm for the past 6 years.

To start with, we have had to go back to the basics of plant genetics, biological functions, physiology and chemistry. Each species and cultivar had to be examined and understood repeatedly. This is because little can be done with restored peatlands or those in the process of restoration, which may take decades. Most plants however, need to be up and ready between 4 – 10 years. It is what it is.

For example, plants in general need N (for growth), P (for fruits, flowers and roots) and K (for water regulation and disease resistance) in a certain form and ratio. Nitrates NO3, phosphates H2PO4, sulphates SO2/4 with calcium Ca2+ and magnesium MG2+ through the roots. Since bogs are acidic, magnesium intake is reduced. If potassium, calcium and phosphorous P2O5 levels become too high, magnesium (chlorophyll for photosynthesis) intake is also affected, yet magnesium is essential for phosphorous uptake. They also need oxygen and carbon from air in the form of carbon dioxide CO2. They will also take hydrogen and oxygen from water to be absorbed through their roots. There are also seven essential micro-nutrients not readily available in the bogs that they need. The list goes on. One particular question to be asked is whether a delivery method, such as the topical foliar application with all that entails for some nutrients, may be one viable solution in some cases where delivery through soil/ roots may not be advisable. What about pests and diseases? Bogs are a perfect environment for pests and diseases, and there have been many deaths and destruction overall. A lot of food for thought, I dare say.

So we have had to focus on every aspect of every plant and tree under trial at Boleysillagh Farm.

Natural farming has its consequences after all. Yet we forge on because we are learning and doing all at the same time.