Trees
Trees are the most significant beings on Earth and the lifeblood of the planet.
They first populated the land almost 400 million years ago and in close harmony with fungi set about creating a habitable environment for almost all land life. Once deeply rooted in our ancient ancestors way of life with mythical status, trees have fallen out of favor in modern times and we're much poorer for it, both in health and spirit.
Fortunately it seems we're reversing this trend and value trees as much alive as when they're dead. We now have a greater understanding of how important they are for the health of the planet and everything living in it.
There are approximately 3 trillion trees on the planet and if there's one thing we can all do to help combat extinction and climate change it's plant more, particularly native ones.
It's estimated around 15 billion trees are cut down each year and 5 billion planted. That means there'll be none left in 300 years which is a worrying thought for the planet.
Shinrinyoku
Forest bathing (taking in the atmosphere of the forest), or Shinrinyoku as the Japanese call it, is now a recognised form of nature therapy proving many benefits to our health and well-being.
Trees expel numerous chemical compounds that our beneficial to other living organisms. For humans, they release compounds that make us feel good, enhance our health and gut flora and even have antibiotic and anti-cancer properties.
If you ever need to unwind, de-stress or simply relax then head to the nearest forest, woodland or coppice for half an hour and wander around.
Ancient Woods
Trees and forest bathing are probably best experienced in the remaining ancient woodlands around the UK. These are woodlands that have existed continuously since 1600 (so are at least 400 years old).
For a list in England see here (select Habitats & Species -> Habitats -> Woodland -> Ancient Woodland), or here on Wikipedia. For Wales see here (in "Preview" tab). Scotland has information here (select "Map data", then "Add Map Layers" and search for "Ancient Woodland Inventory Scotland". Select it and then click "Apply to map". You'll need to zoom in to see the areas).
As with all visits to the countryside remember to leave no trace.
Further Information
Fungi - the unsung hero of ecosystems.
Films
If you should watch any film on trees then it's Call Of The Forest: Trailer.
Also Intelligent Trees: Trailer.
Books
The Hidden Life of Trees: Amazon, Trailer. Reviews: Guardian, Brain Pickings.