I think its really good to write about these things as it helps you analyse the situations and prevent them from happening in future.
I was taken by surprise flying at high density altitude during my hour building in California. I was taking off from South Lake Tahoe (about 6500'AMSL) and it was about 27 Degrees c. the runway length is about 2500m which would seem like ample length for a little PA28. I decided to fill the tanks rather than refuel enroute (to Los Angeles). There were 3 of us on board with little baggage. I was quite confident that runway length would not be an issue and due to rising ground to the South, I decided to depart to the North, over the lake. Unfortunately assumption is the mother of all ***k ups as was later discovered. I did not really consider the terrible climb rate that we would experience at about 9000' density altitude and seemed to have been lured into a false sense of security by the length of the runway. This was made even worse by accepting a slight tail wind (about 4-5 kts) so that I could use the northerly runway.
The result was a take off run that seemed to take forever and a very wobbly lift off. The plane was very reluctant to climb above about 400fpm, and I had to concentrate on keeping the nose down to prevent stalling. We did clear the trees (obviously) but it was far too close for comfort and there was very little room for error. Had I flown into a downdraft or had engine trouble I probably wouldn't be here today, and neither would my passengers.
In retrospect there are a few things I didnt do which i feel i should have:
(1) Check the performance handbook. it only takes a couple of minutes. The fact that the runway was quite long resulted in my assumption that the rest of the takeoff would be ok.
(2) Keep the take off mass down. i could easily have chosen a field enroute for refuelling, and it would have also been a nice addition to my log book.
(3) I still think that using the northerly runway was the correct idea due to the rising ground to the South. I did underestimate the effect of the tailwind though even though it was only light.
These sorts of issues dont normally apply in the UK due to the low elevations but I think that my previous lack of exposure to density altitude increased my vulnerability and complacency.