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Horse chestnut facts and figures:

• This year, Nature's Calendar almost has a UK-wide spread of but still have yet to receive observations from Northern Ireland
• While first sightings may seem a little later than usual we almost certainly have more records to come in, so it's too soon to make a final judgement
• Over the last decade, the UK average date for the first ripe is 17 September. However, recent years, including 2009, have been amongst the earliest of the decade. For example, in 2009 the average was 8 September
• Horse chestnuts are suffering in at least two ways. The first threat is the which arrived in the UK in 2002 and is now widespread in many regions. The larvae of this moth burrow into the leaves and heavy infestations result in leaf browning and drying. Despite the poor looking state of many trees at this time of year, they have carried out most of their growth and fruit ripening by now and don't appear to suffer significantly in the long-term from these infestations.
• Yet there may be a long-term impact on some of the timings of events Nature's Calendar records. At the moment we don't know. As well as recording for Nature's Calendar you can also help scientists discover more about its effects by taking part in an for Conker Tree Science.
• The other, more severe problem is , where tree trunks and branches begin to ooze a brown sticky substance as a result of bacterial infection. The bark then splits and the tree itself becomes progressively sicker (for example, with fewer or prematurely yellowing leaves) as the years progress. This is because of the increasing bark damage. If the bark is killed around the full diameter of the trunk, the tree will die. There is hope: some infected trees do appear to recover
• Bleeding canker disease has been known in the UK since the 1970s but is becoming increasingly widespread
• There's an old wives' tale that spiders hate conkers, so if you keep them in your house the spiders just might stay out! Worth a try?
• On Friday's Autumnwatch we discovered that the annual had been cancelled due to high winds. The event has been held in Northamptonshire since 1965

For the next post in the series it's the turn of the fly agaric fungus, one of our most distinctive fungi.

If any Autumnwatchers out there would like to record the signs of the seasons and help us assess the impact of climate change on wildlife in the UK please visit the .