It is most likely an Agelinid spider, commonly known as funnel web spiders or grass spiders. They make dense webs in sheltered areas, like wood piles or under vegetation. The spider will hang out in a funnel at one end of the web. Leaves or pieces of debris (like the wood chips) can get wound up in the web. In the fall, females lay their egg sacs and enclose them in silk, often with some debris to help camouflage them. 

They are not harmful and probably have just found the woodpile as a good habitat and so a number of them have congregated there.