Alaska hiking: Campfires
The Park Service allows campfires in the park, but only dead wood on the ground may be used for fuel. Much of the alaska hiking terrain of the park is above treeline making the ethics of building a fire somewhat moot. At lower elevations there may be fuel available, however fire building is generally to be avoided in the wilderness. For many, sitting by a crackling fire in the evening is almost a ritual of camping. But in the delicate alpine and tundra environments of backcountry Alaska, a single fire will leave a scar that will remain for years. The best approach is to refrain from making fires on Alaska hiking trips unless you are camping on a riverside gravel or sand bar where all trace of your fire can be eliminated.
Forget about bears - what really strikes fear into the hearts of Alaskan hiking trekkers are mosquitoes. The belief that Alaskan mosquitoes are large enough to carry off small children is a part of the dis-information campaign perpetuated by Alaskans to discourage others from moving here. Alaskan mosquitoes are no larger than elsewhere, but what they lack in size they make up for in sheer numbers.
June is prime bug season and at lower elevations they can get pretty horrific in places. In the mountains however they usually aren't as bad. You might want to carry a headnet if you're planning a trip in June, as well as some bug juice. First time alaska hiking adventurers often overreact to bugs, hosing down with DEET at the first sight of a few mosquitoes, while the locals don't even seem to notice. Sometime around mid August the bugs begin to die off and cease to be a problem even at lower elevations.
There are insect repellants that use natural ingredients such as Citronella which vary in effectiveness though their efficacy is generally short lived at best. DEET remains the most effective and longest lasting repellant. Wearing lighter colored clothing may also help to minimize bug attraction. Clothing with a very tight weave will keep bugs from biting.
Alaska hiking: Drinking Water
Even in the wilds of an Alaska hiking trek the potential for contamination of drinking water exists. Giardia lamblia is the most commonly found microorganism in the backcountry. Cryptosporidium (or Crypto) is also a possibility though much less likely. These microorganisms can be carried in the feces of animals including humans.
The most effective method for destroying these organisms in drinking water is boiling for three minutes. Boiling water in the backcountry however, is not usually very practical because of the time involved and the amount of extra fuel required. Alternatives include filtration or some form of chemical treatment.
There are many different models and styles of filters produced for treating drinking water on alaska hiking adventures, but they aren't all created equal. If you want to filter out Crypto you will need a unit that has a pore size of 0.2 microns or smaller. Beyond that there are features that mostly effect ease of use and convenience such as pump design and whether the filter can be attached directly to a water bottle.
Some models come equipped with a pre-filter or silt filter. But the makers of water filters didn't have the glacial-silt-loaded rivers and streams of Alaska in mind when they designed such features. If stream appears cloudy, even a little bit, then the silt in the water will quickly overwhelm and clog even a brand new filter. Even units that claim they can be field cleaned will be rendered useless. So only use your filter on reasonably clear water.
Disadvantages of filtration pumps are bulk and weight. Once water has been run through the filter it will never be as light as it was out of the box. The spare filter also adds has to be taken into account.
Another method for treating drinking water is with some sort of chemical. Iodine solutions can be used but these don't kill Crypto and taste terrible. Some people have an allergy to iodine.
There are several products that create a chorine dioxide solution, which is the same compound used to treat most city water supplies. The MIOX purifier by MSR creates a similar solution on the fly by passing an electric current through salt brine.
All such products will kill Giardia but there is a question as to the effectiveness of chlorine compounds against Crypto. Destroying Crypto generally requires a much longer waiting time in any case. Wilderness travel generally requires that water be treated on demand, and waiting 8 hours for treatment is not usually practical. Regardless of the method you use, there are trade-offs to be made. But you will want to treat your water in some way on your Alaska hiking trek.