Scholars disagree over the type of the tree. Some people have tried to determine its type by looking into books of hadith, athaar, and the Bible.
But is this issue worth all the debate? Imaam Abu Ja'far at-Tabaree, who was a Mufassir (scholar of tafsir), didn't think so:
وذلك عِلمٌ، إذا عُلم لم ينفع العالمَ به علمه، وإن جهله جاهل لم يضرَّه جهلُه به
"For such type of knowledge: If one knows it, then his knowledge of it doesn't benefit him, and if one is ignorant of it, then his ignorance of it doesn't harm him."*
There are other examples of trivial details that we need to ignore. For example Allah (swt) in Suratul Kahf (chapter 18 of the Quran) talks about how people debated about the number of the Men of the Cave, but after mentioning this He doesn't tell us their real number, because it is not important. Instead He asks us not to dwell on it.
We can look at the Quran to find out what Allah (swt) wants us to focus on. For example, Allah (swt) keeps reminding us of the Day of Judgment, and He keeps describing Paradise and Hell. When Allah constantly reminds us of something, it means He wants us to think about it.
Points to remember
- Don't busy yourself with trivial details that have no benefit for you in this life or the Hereafter. It wastes your time and makes you ignore more important matters.
- To determine what is important, read the Quran. Certain subjects are repeated constantly—these are your priorities.
- The point of this post is not to discourage you from seeking details (you can memorize all the details about Paradise that are mentioned in the Quran, this will be a great Islamic motivation for you); we only mean useless details.
*See Tafseer at-Tabaree, commentary on verse 35 of Surah al-Baqarah, as quoted by Imaam ibn Katheer in his Tafseer of the same verse.