The microclimate close to the forest floor strongly influences the survival and growth of tree seedlings. Data on the variability in forest microclimate below two metres has been collected in plots of different density in a Sitka spruce plantation at Harwood forest in Northumberland, UK. The data showed similarities to previous studies; strong diurnal variation; relatively constant temperature profile and a wind speed sub-maximum in the vertical wind profile. Above canopy data shows that windspeeds of >4.5m/s are required to penetrate the canopy, and cross correlation shows a three hour lag in temperature from above the canopy to below two metres. The data is currently being used to validate a 1-D model for predicting the microclimate close to the ground in forest stands, to be used as a tool to assess the potential for natural regeneration. Further data is being collected from a series of forest stands of different spacings (four, six and eight metres) in Cloich forest, SE Scotland.