Trees are being hit by dangers such as the oak processionary moth, which can also cause breathing problems in people, the "terrestrial biodiversity climate change impacts report card" drawn up for the Government shows.
And the UK's climate will become more suitable to invasive pests and diseases, including those which have an impact on a wide range of native plant species.
The new overview by the Living with Environmental Change partnership draws together the latest evidence to provide information on the impact of climate change on the countryside now and in the future.
Many spring events, from frog spawning to flowers blossoming, are happening earlier, with the danger that the life-cycles of dependent species are becoming out of sync, the report said.
It also revealed that many dragonflies, butterflies and woodlice are moving their ranges north, while new species of insect have colonised the UK from Europe.
Warmer winters are affecting the hibernation of species such as hedgehogs and dormice, with potential impacts on their survival and breeding success.
Dr Mike Morecroft, from Natural England, who led the development of the overview, said: "This report card shows strong evidence from a large number of different scientific studies that the natural world has started to respond to climate change.
"It also shows the range and complexity of these changes: some species and habitats are much more sensitive than others."