Beyond the Trees: In conversation with Carmen Romeralo – CSIC

Carmen Romeralo is a researcher in the Institute of Forest Science (ICIFOR). It is a public research institute located in Madrid, within the Spanish Research Council, CSIC. Carmen brings 20 years of forest pathology experience to the OptiForValue project.  Within the project, her work on Work Package 2, OptiManage, is focused on finding indicators of forest health, and how different forest management practices may influence the microbes present in the forest. 

Watch the video interview below!

Carmen, how did you initially get interested in forestry? 

Carmen: It was from my childhood that I always have loved nature. Initially, I wanted to study physics because it was my passion in high school but then I remembered my sister telling me, “But you like nature very much, why don’t you study something that combines physics and mathematics with nature?”. This was around one month before deciding to start university, so it was very last minute! Then I said “okay, that’s a good idea!” and I don’t regret it because I really like the forestry world and everything that is related to it.  

What are your primary research interests within this field? 

Carmen: I am a forest pathologist, so I work with microbes that produce disease to trees. Within pathology, I have specialized in fungi. I sometimes work with bacteria, but they are tricky and difficult to work with. 

I work both with pathogens, so fungi that can produce disease to trees, and also with endophytes, that are like beneficial fungi for the trees. They confer some protection to trees, and they interact with pathogens in a way that we are trying to find out exactly how they manage to protect the trees from these attacks. So, I work both with endophytes, the beneficial fungi for the trees, and also with forest pathogens.  

What is your role within the Opti4Value project? 

Carmen: I am currently working in Work Package 2 of OptiForValue, which is led by our institution, the Spanish Research Council and the Institute of Forest Research. Inside this package, I am trying to find indicators of forest health.  

We are trying to describe first, whether the mixing of tree species is good or bad for the forest in terms of what microbes lives inside the tree. As I mentioned previously, some microbes and some endophytes are good for the trees, and we know that the composition of this fungi community sometimes changes with the tree species present and with the forest management. Therefore, we are also trying to find out how this composition of microbes is changing with different forest management practices, such as clear cuts. 

In relation to composition, we wanted to answer questions like – if the trees are very related, so for example are pine species and so phylogenetically are very close, we hypothesize that the composition of the community will be similar. But what happens if the pine are alongside oaks or beech, that are a bit more distant? We hypothesize that the community will change also with this composition of tree species.  

We are testing in Spain, where we have several plots of Scots pine, Pinus silvestris, which is the main species here. We are studying forest management in plots of Scots pine and we are studying the mixtures of pine in an area with maritime pine and beech.  

Have you made any key findings as part of the project? 

Carmen: We still don’t know because we haven’t analysed all data. We have sampled all of the plots and collected around 200 trunk samples. We have sampled the endophytes that live inside the trunk, because we cannot reach the leaves, they are too high. Some of the plots are over 100 years, so we cannot reach the leaves. 

We have taken cores from active tissue in the trunk of the tree. This active part, the vascular cambium, is where the tree grows and this is what creates the rings of the tree. We have more than ten plots and now we are analysing the data. 

Are there any big research challenges for you in this, and do you plan to overcome them in certain ways? 

Carmen: The main challenge for this task is to identify which endophytes are protecting the trees. From the results, we have an abundance matrix, with columns of abundance, and for every tissue we have a list of more than 400 taxa. It is very tricky to assign a function to these taxa, to the species of the fungi that live inside, as fungi are very flexible and sometimes the good ones, the ones that are living in a symbiotic relationship, can change into a pathogenic style. Therefore, sometimes it’s very tricky to find out what are the functions of the fungi. 

We will compare the community in the healthier plots with the others to try to find out. It’s true that there are some databases that assign a trophic mode or a functional style to every fungi, but as I said before, these functions can change with the environment and with the context, because they are very flexible. So, this is a big challenge that we face. 

Why is this work valuable? 

Carmen: I think it’s very valuable because to my knowledge, it’s the first time that we are doing research on how forest management affects these communities. There is a lot of research on mycorrhizas and the soil, because of course when you reduce density and you reduce trees in a plot, the soil is much more exposed to the sun and the environmental conditions change, but there is not that much research on what happens inside the trunk. We know that it’s important for the tree to grow because these fungi maintain a symbiotic relationship that can change.