We will be in the LA for a short period of time and we have one day that we want to explore outside of the LA area (we are going to Disneyland 1 day also). We are probably looking for something more in "nature" than "touristy".

I know that Joshua Tree NP is not too far and that is a possibility, would anyone recommend that? What about other places? Any redwoods within driving distances for a day?

We are 2 young adults.

An LA friend took me hiking at Descanto Gardens. (I think that is how you spell it??)It was a nice spot with lots of trails. We went after we toured the Norton Simon museum in Pasadena, which I loved....I think they are near each other...I was a passenger just enjoying the day!!
Have fun.

Joshua Tree is great. However, given your short time in the LA area, you might want to hit one of the urban oases in the metro region. Say, Descanso Gardens (La Cañada Flintridge), or the Huntington Library (San Marino-- beautiful grounds), or the gardens at the Getty Center (West LA).

Although redwoods have been planted here and there in southern California, you're probably thinking of the giant redwoods one finds in northern CA. The coastal deserts of southern CA are too dry to naturally support redwoods, so the giant trees you see up north aren't found here.

To add to the (semi-) urban retreats:

I thoroughly enjoyed hiking in the Santa Monica Mountains National Park. There is a visitor center in Thousand Oaks that will readily provide you with maps and suggestions of where to go.

http://www.nps.gov/samo/index.htm

For instance, in the Rancho Sierra Vista area, there is a nice trail leading you to a hidden waterfall after passing by an inforation center on the history of the local population of the Chumash Native Americans.

http://www.nps.gov/samo/pdffiles/rsv.pdf

enjoy the day and then head off to laguna beach for sunset and dinner.
another fun day trip would be out to catalina island. you can rent bikes or do some kayaking.

I second the Catalina recommendation.

I love Joshua Tree but it will be at least a three hour trip to get out there and with the huge fire, it is not the place to be this month, and possibly not for the rest of the year because of the fire damage. I also love Descanso Gardens, Huntington Library, or either of the Getty Museums. The main Getty has beautiful art and the Villa in Malibu is a beautiful replica of an ancient Greek villa. I'd go to Descanso Gardens but any of those would be good choices.

Depending on when you are going, Joshua tree is HOT. It is 11 pm here now and is 89 degrees at Joshua Tree, and is supposed to be 103 degrees tomorrow. Catalina Island is a nice boat ride (about an hour or so) and a cute little port with sightseeing or snorkling. See www.catalina.com for info. Or the beaches in OC are lovely as well (Newport or Corona Del Mar or Balboa Island).