Budburst high and budburst low

Christine Tansey's picture

On my last few visits to the woods I have been reminded of the sometimes tricky nature of monitoring the budburst of trees. How easy it is to score budburst often depends on several things; the tree species, how tall the tree is, whether there are easily reachable branches to check, and what the light is like on the day of your observation. But don’t panic! If you’re not confident about your budburst observations, make sure you keep recording until leaves start to appear. Scanning a mature tree for the first leaf shapes is much easier than looking for budburst, and the first leafing records will be essential for the research based on Track a Tree that I’ll be undertaking over the next year.

In the meantime I thought I’d write down our recommendations for scoring budburst. Firstly, here’s a quick reminder of our definitions of budburst and leafing:

Budburst - The green of new leaves is seen protruding from between the scales of the swollen and elongated bud.

First leaf - When the first leaf is fully open and is recognisably the shape, if not the full size, of the adult leaf. For compound leaves like Ash or Rowan the leaf must be erect but the leaflets don’t need to be.

If you have a tree with branches low enough to access and observe close-up, you may be able to see budburst of species with smaller buds, such as silver birch when it reaches a stage like the examples below:

                   Silver birch                                                 Sycamore

                  

If your tree only has branches that you can observe through binoculars, you should aim to record budburst when you see a clear change in bud shape that shows the leaves starting to protrude, more like this:

                Silver birch                                                   Sycamore

               

If you are unsure about whether you can see budburst on high branches, you may find that visiting it on another day when direct sunlight is hitting the branches can reveal the colour of new leaves. We’d like you to send in records when you are confident you have seen the green (or off-green!) of the new leaves starting to protrude through the bud.

While we’re talking budburst, I thought it might be helpful to go over our scoring categories for tree phenology. Remember that you may need to score the same category for several visits in a row if the tree phenology had not advanced much since the last time you saw it.

  • No budburst observed. Record this when you cannot see budburst on any of the branches you observe on your tree.
  • First budburst: Record this the first time you observe budburst anywhere on your chosen tree. Remember that we don’t expect you to record the very first budburst on your tree, but the date of the first time you saw budburst.
  • Partial budburst: Record this when you observed first budburst on an earlier visit, but budburst has not yet been reached on all the tree’s branches.
  • Entire tree budburst: Record this when budburst appears to be present on all the branches you observe on your chosen tree.
  • First leaf: Record this on the first visit that you observe leafing anywhere on your chosen tree.
  • Partial leaf: Record this when you observed first leafing on an earlier visit, but leafing has not been reached on all the tree’s branches.
  • Entire tree in leaf: Record this when all branches you observe on your tree have reached leafing.

At the moment, the Track a Tree online recording system only allows you to submit one of the above categories for tree phenology. This means that the first time you observe an event such as first leaf, we need that observation to be submitted even if some of the tree branches have not yet budburst.

As ever, we are happy to answer any questions you might have about recording – so do get in touch via our recorders forum or by emailing info@trackatree.org.uk.

Thanks for all your help and keep enjoying spring in the woods!