Why forestry should consider somatic embryogenesis

THE UK needs to plant more trees, from both an environmental and an economic perspective. And yet, to date, every target set by the UK Government has been missed by a substantial margin.

While there are many different factors that are influencing this, the role of mother nature is having a significant impact on the quality of seedlings produced each year, and how well these survive once planted.

As uncertainty grows around the UK’s weather and the ongoing impact of climate change, as a sector, we need to explore and discuss all available options on what can be done to ensure a healthy and reliable crop of seedlings each year, so that we’re able to meet targets around tree planting. As part of these discussions, we should examine the role that technology can play and how it can help us to advance our knowledge, learning and ability to improve our sector. 

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As of right now, most of our tree seeds are produced through open pollination which results in only the mother being known and is often referred to as a ‘half-sibling’ family. The consequences of this are that not all potential genetic gains are realised, and our orchards are full of seedlings that have uneven genetic contributions and no certainty over how successful seed crops will be. 

The other current option used within our industry is controlled pollination, which provides huge benefits when it comes to the quality of genetics of the seedlings. Forests planted with ‘full sibling’ trees that come from controlled pollination have been shown to produce 130 per cent more sawn timber per hectare without deterioration in graded timber. However, this type of pollination is extremely labour intensive, which makes seeds expensive and in very short supply and unfortunately can take several years before the genetic gains are to be fully realised.

Some of the science currently in its infancy in our sector has significant potential to provide solutions to many of the problems we are facing around the growing of tree seedlings. One such science is somatic embryogenesis. While it presently has a somewhat Marmite reputation – with those for and against it – we need to start the conversations around the use of such technology. It has the potential to offer our sector so much, but its approval will require years of planning and policy to ensure that the benefits of such technology are realised in a positive manner.

For those new to somatic embryogenesis, it is an advanced vegetative propagation technology where clonal embryos are multiplied and germinated under laboratory conditions. This is a complex process with several inter-dependant stages that mimic the developmental stages of seeds under natural conditions. It provides a rapid, efficient means of producing thousands of identical copies from a single seed. For us as an industry, the benefits could be instrumental in helping us to meet targets through a better conversion rate and quicker turnaround time from seeds to plants than the traditional vegetative propagation route. 

But somatic embryogenesis is not without its critics or potential pitfalls, and we would do a disservice to our industry not to discuss them. However, I strongly believe that these can be managed through industry-wide policy and even legislation to ensure that the benefits are properly accomplished.

Current concerns centre around genetic uniformity and the loss of genetic diversity as it can make trees more susceptible to diseases, pests and environmental stresses. But it is also worth flipping the argument around genetics to look at what it can do for our industry. At a time of so much uncertainty around climate change and the long-term changes it will bring, somatic embryogenesis can rapidly diversify planting stock in response to changing environmental conditions through producing large numbers of new species or hybrids. This can be engineered in a way that these new varieties show resistance to emerging pests and disease or drought resilience, whilst ensuring that high levels of genetic diversity are maintained in our forests.

There is also the role this science can play in our sustainability drive. As it stands, the UK imports more timber than any other country except China. This is great neither for the environment or our economic sustainability. With more government targets around net zero, timber has a significant part in the drive for net zero, especially in industries such as construction. Somatic embryogenesis could help to realise between 50–70 per cent extra UK sawn timber per hectare, which would help to reduce our reliance on imported timber. 

It is also important to note that we are in the early stages of somatic embryogenesis innovation, which currently present their own challenges. Maelor has invested in a state-of-the-art laboratory which was established with the help of world-renowned tissue culturist and tree-breeding expert Dr David Thompson. It is here that we have started work on somatic embryogenesis with the aim of producing thousands of trees from a single embryo or seed. 

However, not all UK-native trees respond well to somatic embryogenesis, and we’re still learning how to ensure quality and consistency of regenerated plants on a commercial scale. But these are challenges that as an industry we can overcome through collaborative working, sharing of research and a consensus to overcome these barriers. 

If other countries can start to explore somatic embryogenesis and put it into production, including New Zealand and in North America, then the UK should look to them to learn from, adapt and develop their policies further so that they are suitable for the UK forestry sector.

There is no silver bullet in the form of answers as to how to overcome these concerns, but with huge potential benefits to be realised, we should be doing all we can to find solutions.