As far as you can go – Tree Fern Regeneration

Scattered in amongst this were a couple of examples of the weirdest and most wonderful plants on the slopes, the St Helena Tree Fern, but then we turned a corner and were in amongst one of the oldest remaining stands of that plant.  Everywhere I looked these dark brown trunks with wispy fronds covered the hillside.  While I did not find the flax an unpleasant ground cover, there was a magic of the tree fern forest, and I could but imagine what the whole area looked like when it was a mixture of these ferns and the black cabbage trees.  On a later walk around with Rebecca I got in amongst the tree fern forests and you were able to touch the trunks themselves.  While they were thick and several metres tall, they were incredibly fragile.  Incised with long deep channels, the water easily got inside the trunks and you could see plenty of evidence of rotting.  If you touched the surface you realised it was a soft sponge and all too easily damaged or snapped off.  In the harsh winds up here on the peaks there were plenty of uprooted ferns, but they continued to grow at the horizontal, or were gradually rotting away into the ground to feed the next generation.  Most tree ferns I have seen have an even canopy either side of the trunk but these St Helena ferns tended to bend over one side, either due to their genetics of the prevailing winds.

Rebecca enthused about the environment created in amongst these plants.  It was far more biodiverse than the flax with more layers and niche habitats for all the lower plants, the mosses, ordinary ferns and liverworts to thrive in, as well as the fungi.  Then there were all the  insects, the spiders and the birds, and the various other animals that have found their way on to St Helena and refuge in amongst the ferns.  All these niches in themselves have produced a wide variety of species within these orders which you may not only not find anywhere else than St Helena, but even within St Helena there are particular areas where species have specialized.

As well as the mature stands of tree ferns, I was shown where there were five, four , three year old plantations on the reclaimed flax parcels.  Each group of parcels had names related to the little valleys they were in, the peaks and tracks that were named in past centuries, or with reference to a significant St Helenian, and then each individual parcel was numbered.  So you might have an area called Stitch’s Ridge II.   Rebecca wanted to visualise the progress being made on the clearance of the invasives, planting programmes and monitoring of the health of the plants.  So I spent many an hour up at the ANRD log cabin or on the large round table in the National Trust Office pulling together the map of the parcels, building a database to allow all this information to be collated, and running the summaries and programmes to allow the data to be charted or mapped in the GIS.  It was a tough ask for three weeks, but very interesting work.  Although the people conducting the conservation on island were used to maps, they had not see how the power of GIS could unlock so many more possibilities of analyzing and visualising the patterns on the ground of endemic regrowth.

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