A little guessing game to get us going this morning. How old do you think these trees are?

On the left with the trunk in sunshine is a Rowan, on the right an Elm with its trunk in shade, and in the middle are three Silver Birches, planted close together with a froth of leaves coming right down to the base.

To give you a better sense of scale to aid your guess, here I am at the foot of the Birches, which must be now 8 metres (25 foot) or so high:

What I find amazing is that I only planted these trees in 2015, and the saplings at that stage were three years old. So that makes them just 10 years old. Boy, have they grown! In human terms, they may no longer be babies but they are still very much children. I like to think that my trees have just moved up to High School, literally!

Not only are my trees on a major growing spurt, but they are already buzzing with birds and insects, and producing lots of flowers, seeds and berries, such as these few dangling berries that are left on the Rowan that my Blackbirds don't quite have the acrobatic skills to get.

We're now fast approaching tree-planting season, which for most broadleaved trees is done in winter. Not only is that the best time for the trees because they are dormant, but it is also the cheapest and easiest way to plant. You can buy little 'whips' (young saplings) for just a few pounds, and they come bare-rooted which means you're not having to manhandle a heavy pot and rootball.

Check out our Nature on your Doorstep guide to planting trees, including choosing the right one for you. There's a tree for every outside space, whether you have a large garden or just a patio or balcony.

And in these cash-strapped times, why not collect a tree seed or two for free from friends' gardens or on a nature walk, and that way you can really be a parent from birth. Hopefully, as the photos from my garden show, you then won't have long to wait for your offspring to grow into something magnificent that you can enjoy, and hopefully will still be around for future generations, too.

It is amazing to think that you tree could still be going into the 22nd Century; goodness knows how many Prime Ministers my Birches will have seen by then!

If you want to drop by my RSPB wildlife gardening blog, it is updated every Friday, and I'd love to see you there - www.rspb.org.uk/community/blogs/hfw