My Lords, it is a great pleasure to follow the noble Duke, the Duke of Wellington. I absolutely agree with him that no two pieces of land are exactly the same.
I support Amendment 260 in the names of the noble Baronesses, Lady Young and Lady Jones, the noble Earl, Lord Caithness, and the noble Lord, Lord
Teverson, in particular proposed subsection (3) about the percentage of native woodland and the new native woodland that is achieved by natural regeneration.
I draw the Committee’s attention to the work of Professor Simard at the University of British Columbia. When she was 20, she was put to work on commercial forestry—the process of clear-cutting large areas of old-growth forest and planting individual seedlings, pine or birch, in neat and regimented rows. The thinking was that, without any competitors, trees would grow faster, taller and stronger. Instead, they were more frequently found to be vulnerable to disease and climatic stress than the older trees, which shared their patch of soil with other plants, mosses, firs and associated lifeforms. In particular, she studied the newly planted Douglas firs—great giants which provided valuable wood to the logging companies. Ten per cent of those plants invariably got sick and died whenever nearby aspen, paper birch and cottonwood were removed. Initially, when she was 20—she is now 60—she did not know why, because the trees had plenty of light and water, more than the old trees in the crowded forest. She worked through her life and in the end revealed and became the inventor of what is known as the “wood wide web”. The forest, she wrote, is like the internet, but instead of computers linked by radio waves, the trees are connected by fungi. There are centres and satellites, with the oldest trees as the biggest communication hubs. When the piece with her theory was published in Nature in 1997, it had that title of “Wood Wide Web”, and the name has stuck.
Once the underground pattern is understood, it is easy to see how seedlings can emerge in clear ground, because they have been nurtured underground by other trees, waiting for their moment to start growing. They are being fed by the mother trees—the central hub that the saplings and seedlings spring from—with threads of different fungal species, of different colours and weights, linking them layer upon layer in the strong and complex web. When the forest is cleared and the mother trees are cut down, the forests lose their way.
Professor Simard’s discoveries have kept coming, and she now finds that trees support each other in times of stress, drought or disease, and they can communicate needs and send supplies. Since Darwin, biologists have always maintained that survival is all about the selfish gene, doing anything to get ahead in the evolutionary race. But her work tosses that on its head.
We now understand that monocultures, whether of crops, trees or any plant species, are not healthy. My plea would be that in the tree strategy we understand that all new planted forests and woods must be of multiple trees. I absolutely agree with the noble Earl, Lord Devon, when he says we should start experimenting with trees, especially in the south of England, that will thrive in our newly warmed environment. But please do not let us spend all our tree-planting money on monocultures which end up leaving dead soil beneath that is not home to myriad mosses and animals and, in fact, ends up sequestering much less carbon than a mixed forest growth.