At least in North America you should not source your logs from as close as possible and no more then 50 miles away (possibly much closer based on your area) to prevent spread of any of these 53 pests or wood diseases spread by moving logs:
Ambrosia beetle
Asian Gypsy Moth
Asian Longhorned Beetle
Balsam Woolly Adelgid
Banded Elm Bark Beetle
Bromeliad Weevil
Brown Spruce Longhorned Beetle
Cactus Moth
Chestnut Gall Wasp
Citrus Longhorned Beetle
Common Pine Shoot Beetle
Cycad Aulacaspis Scale
Emerald Ash Borer
Erythrina Gall Wasp
Eurasian Nun Moth
European Gypsy Moth
European Oak Bark Beetle
European Spruce Beetle
Golden Haired Pine Bark Beetle
Goldspotted oak borer
Harrisia cactus mealybug
Hemlock Woolly Adelgid
Larch Casebearer
Larger Pine Shoot Beetle
Lobate Lac Scale
Mediterranean Pine Engraver Beetle
Pine Flat Bug
Polyphagous shot hole borer
Red-Haired Pine Bark Beetle
Sirex Woodwasp
Soapberry Borer
Spruce Aphid
Viburnum leaf beetle
Walnut Twig Beetle
Ohi'a Rust
Alder Dieback
Amylostereum complex
Beech Bark Disease
Butternut Canker
Chestnut Blight
Dogwood Anthracnose Disease
Dutch Elm Disease
European Larch Canker
Fusarium fungus
Laurel Wilt
Oak Dieback
Phytophthora kernoviae
Phytophthora Root Rot
Pine Pitch Canker
Port-Orford-Cedar Root Disease
Sudden Oak Death Syndrome
Thousand Canker Disease
White Pine Blister Rust
