Have you noticed your Pine or Spruce tree's needles turning brown or purple-ish? Do they look similar to the photos here? Most likely your trees have frost damage, and will likely make a full recovery. Read below for a detailed explanation from Brett:
The damage you're seeing in these Pines is the result of the record-setting frost which occurred the 1st week of October. This intense, sudden drop of temperature, that early in the Fall caught conifers of all species 'off guard' before they had even begun hardening off for the Winter.
This resulted in the chloroplast cells in the tissues freezing. Some burst outright, others lost cell wall rigidity and became 'leaky' while others became weakened.
Following this freeze, the trees did progress into their normal transition into 'dormancy' (conifers don't ever go into complete dormancy but instead merely slow down both respiration and transpiration).
Damage at this stage in the game varied by the extent of the cellular damage incurred; some showing immediate symptoms, some not showing any visible damage.
Now, as temperatures increase and daylight hours increase, these trees are coming out of dormancy, respiration kicks in gear, leading to increased transpiration and the moisture in these damaged, ruptured, and weakened cells are being wicked dry, leading to desiccation and necrosis.
I expect as temperatures increase, along with wind events, the damaged cells which were still OK during cooler, wetter and shorter days will begin to show symptoms as well.
The bottom line is that I believe that this will get a bit worse before it gets better.
Now the good news; of the hundreds of trees I have observed, very few had lost the buds which are set to 'candle out' for this season. These buds and the twigs appear supple and viable still so I do expect to see new growth emerging this season. Depending on the damage, the damaged needles may drop or hang on for quite some time. Those which remain will lead to a somewhat displeasing aesthetic appearance but ultimately rebound over time.
There isn't anything that will 'fix' the problem and I would avoid the temptation of pouring water to the problem. Pines don't like soggy feet. Provide adequate water to keep the soil moist but not saturated. Water during times of increased temperatures and especially when windy conditions persist.
I hope this information is helpful to you, and please don't hesitate to call me if you have any questions or if I can be of any assistance to you.
All the best,